diff --git a/README.md b/README.md
index 15da46fa14..dc2082af06 100644
--- a/README.md
+++ b/README.md
@@ -85,6 +85,10 @@ http_archive(
 load("@io_bazel_rules_closure//closure:defs.bzl", "closure_repositories")
 
 closure_repositories()
+
+load("@io_bazel_rules_closure//closure:defs.bzl", "closure_register_toolchains")
+
+closure_register_toolchains()
 ```
 
 You are not required to install the Closure Tools, PhantomJS, or anything else
diff --git a/WORKSPACE b/WORKSPACE
index cb9eee519f..a0a1fb04f9 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -6,20 +6,9 @@ load("//closure:repositories.bzl", "closure_repositories")
 
 closure_repositories()
 
-http_archive(
-    name = "zlib",
-    build_file = "//:third_party/zlib.BUILD",
-    sha256 = "c3e5e9fdd5004dcb542feda5ee4f0ff0744628baf8ed2dd5d66f8ca1197cb1a1",
-    strip_prefix = "zlib-1.2.11",
-    urls = ["https://zlib.net/zlib-1.2.11.tar.gz"],
-)
+load("//closure:toolchains.bzl", "closure_register_toolchains")
 
-http_archive(
-    name = "bazel_skylib",
-    sha256 = "bbccf674aa441c266df9894182d80de104cabd19be98be002f6d478aaa31574d",
-    strip_prefix = "bazel-skylib-2169ae1c374aab4a09aa90e65efe1a3aad4e279b",
-    urls = ["https://github.com/bazelbuild/bazel-skylib/archive/2169ae1c374aab4a09aa90e65efe1a3aad4e279b.tar.gz"],
-)
+closure_register_toolchains()
 
 java_import_external(
     name = "com_google_guava_testlib",
diff --git a/closure/defs.bzl b/closure/defs.bzl
index 0fd1d54afb..045a5aae85 100644
--- a/closure/defs.bzl
+++ b/closure/defs.bzl
@@ -29,6 +29,7 @@ load("//closure/testing:closure_js_test.bzl", _closure_js_test = "closure_js_tes
 load("//closure/testing:phantomjs_test.bzl", _phantomjs_test = "phantomjs_test")
 load("//closure:filegroup_external.bzl", _filegroup_external = "filegroup_external")
 load("//closure:repositories.bzl", _closure_repositories = "closure_repositories")
+load("//closure:toolchains.bzl", _closure_register_toolchains = "closure_register_toolchains")
 load("//closure:webfiles/web_library.bzl", _web_library = "web_library")
 load("//closure:webfiles/web_library_external.bzl", _web_library_external = "web_library_external")
 
@@ -50,5 +51,6 @@ closure_js_test = _closure_js_test
 phantomjs_test = _phantomjs_test
 filegroup_external = _filegroup_external
 closure_repositories = _closure_repositories
+closure_register_toolchains = _closure_register_toolchains
 web_library = _web_library
 web_library_external = _web_library_external
diff --git a/closure/protobuf/BUILD b/closure/protobuf/BUILD
index 91f951a592..4a8124bff1 100644
--- a/closure/protobuf/BUILD
+++ b/closure/protobuf/BUILD
@@ -36,3 +36,11 @@ closure_js_library(
         "//closure/library/string",
     ],
 )
+
+closure_js_library(
+    name = "runtime",
+    exports = [
+        ":jspb",
+        "//closure/library/array",
+    ],
+)
diff --git a/closure/protobuf/closure_proto_library.bzl b/closure/protobuf/closure_proto_library.bzl
index f3ee6fb2b6..0f5f13a106 100644
--- a/closure/protobuf/closure_proto_library.bzl
+++ b/closure/protobuf/closure_proto_library.bzl
@@ -17,79 +17,50 @@
 
 load("//closure/compiler:closure_js_library.bzl", "create_closure_js_library")
 load("//closure/private:defs.bzl", "CLOSURE_JS_TOOLCHAIN_ATTRS", "unfurl")
+load("@build_bazel_rules_proto//proto:proto_common.bzl", "proto_common")
 
-# This was borrowed from Rules Go, licensed under Apache 2.
-# https://github.com/bazelbuild/rules_go/blob/67f44035d84a352cffb9465159e199066ecb814c/proto/compiler.bzl#L72
-def _proto_path(proto):
-    path = proto.path
-    root = proto.root.path
-    ws = proto.owner.workspace_root
-    if path.startswith(root):
-        path = path[len(root):]
-    if path.startswith("/"):
-        path = path[1:]
-    if path.startswith(ws):
-        path = path[len(ws):]
-    if path.startswith("/"):
-        path = path[1:]
-    return path
-
-def _proto_include_path(proto):
-    path = proto.path[:-len(_proto_path(proto))]
-    if not path:
-        return "."
-    if path.endswith("/"):
-        path = path[:-1]
-    return path
-
-def _proto_include_paths(protos):
-    return depset([_proto_include_path(proto) for proto in protos.to_list()])
-
-def _generate_closure_js_progress_message(name):
-    # TODO(yannic): Add a better message?
-    return "Generating JavaScript Protocol Buffer %s" % name
-
-def _generate_closure_js(target, ctx):
-    # Support only `import_style=closure`, and always add
-    # |goog.require()| for enums.
-    js_out_options = [
-        "import_style=closure",
-        "library=%s" % ctx.label.name,
-        "add_require_for_enums",
-    ]
-    if getattr(ctx.rule.attr, "testonly", False):
-        js_out_options.append("testonly")
-    js = ctx.actions.declare_file("%s.js" % ctx.label.name)
-
-    # Add include paths for all proto files,
-    # to avoid copying/linking the files for every target.
-    protos = target[ProtoInfo].transitive_imports
-    args = ["-I%s" % p for p in _proto_include_paths(protos).to_list()]
-
-    out_options = ",".join(js_out_options)
-    out_path = "/".join(js.path.split("/")[:-1])
-    args += ["--js_out=%s:%s" % (out_options, out_path)]
-
-    # Add paths of protos we generate files for.
-    args += [file.path for file in target[ProtoInfo].direct_sources]
-
-    ctx.actions.run(
-        inputs = protos,
-        outputs = [js],
-        executable = ctx.executable._protoc,
-        arguments = args,
-        progress_message =
-            _generate_closure_js_progress_message(ctx.rule.attr.name),
-    )
+def _closure_proto_output_name(src):
+    # src is of format <path/to/file>.proto
+    return ["{}.js".format(src[:-6])]
+
+def _closure_proto_options(params):
+    options = []
+
+    # The framework in rules_protobuf requires that we generate one output
+    # file for every input file.
+    options.append("one_output_file_per_input_file")
+
+    # Only `import_style=closure` is supported for now.
+    # See https://github.com/grpc/grpc-web/pull/260#issuecomment-415443448
+    options.append("import_style=closure")
+
+    # Enums are allways |goog.require()|'d in the generated files to avoid
+    # namespace-not-provided if no library |goog.require()|'s them.
+    options.append("add_require_for_enums")
 
-    return js
+    # If the proto_library is marked as testonly, tell protoc to add
+    # |goog.setTestOnly()| to the generated code.
+    if params.testonly:
+        options.append("testonly")
+
+    return ",".join(options)
 
 def _closure_proto_aspect_impl(target, ctx):
-    js = _generate_closure_js(target, ctx)
+    srcs = proto_common.lang_proto_aspect_impl(
+        actions = ctx.actions,
+        toolchain = ctx.toolchains[proto_common.TOOLCHAIN_TYPE],
+        flavor = "Closure",
+        get_generator_options = _closure_proto_options,
+        get_generator_options_params = struct(
+            testonly = getattr(ctx.rule.attr, "testonly", False),
+        ),
+        get_output_files = _closure_proto_output_name,
+        language = "js",
+        target = target,
+    )
 
-    srcs = depset([js])
     deps = unfurl(ctx.rule.attr.deps, provider = "closure_js_library")
-    deps += [ctx.attr._closure_library, ctx.attr._closure_protobuf_jspb]
+    deps += [ctx.attr._closure_protobuf_runtime]
 
     suppress = [
         "missingProperties",
@@ -100,27 +71,20 @@ def _closure_proto_aspect_impl(target, ctx):
     return struct(
         exports = library.exports,
         closure_js_library = library.closure_js_library,
-        # The usual suspects are exported as runfiles, in addition to raw source.
-        runfiles = ctx.runfiles(files = [js]),
     )
 
-closure_proto_aspect = aspect(
-    attr_aspects = ["deps"],
+closure_proto_aspect = proto_common.lang_proto_aspect(
     attrs = dict({
         # internal only
-        "_protoc": attr.label(
-            default = Label("@com_google_protobuf//:protoc"),
-            executable = True,
-            cfg = "host",
-        ),
-        "_closure_library": attr.label(
-            default = Label("//closure/library/array"),
-        ),
-        "_closure_protobuf_jspb": attr.label(
-            default = Label("//closure/protobuf:jspb"),
+        "_closure_protobuf_runtime": attr.label(
+            default = Label("//closure/protobuf:runtime"),
         ),
     }, **CLOSURE_JS_TOOLCHAIN_ATTRS),
     implementation = _closure_proto_aspect_impl,
+    provides = [
+        "closure_js_library",
+        "exports",
+    ],
 )
 
 _error_multiple_deps = "".join([
diff --git a/closure/protobuf/test/BUILD b/closure/protobuf/test/BUILD
index addf5387e9..777bd78aa6 100644
--- a/closure/protobuf/test/BUILD
+++ b/closure/protobuf/test/BUILD
@@ -19,6 +19,90 @@ licenses(["notice"])  # Apache 2.0
 load("//closure/compiler:closure_js_library.bzl", "closure_js_library")
 load("//closure/protobuf:closure_proto_library.bzl", "closure_proto_library")
 load("//closure/testing:closure_js_test.bzl", "closure_js_test")
+load("@build_bazel_rules_proto//proto:proto_library.bzl", "proto_library")
+
+# TODO(yannic): Add test for attr `proto_source_root`.
+
+proto_library(
+    name = "add_prefix_proto",
+    srcs = [
+        "add_prefix.proto",
+    ],
+    import_prefix = "foo",
+)
+
+closure_proto_library(
+    name = "add_prefix_closure_proto",
+    deps = [
+        ":add_prefix_proto",
+    ],
+)
+
+proto_library(
+    name = "add_and_strip_prefix_proto",
+    srcs = [
+        "import_prefix/add_and_strip_prefix.proto",
+    ],
+    import_prefix = "bar",
+    strip_import_prefix = "import_prefix",
+)
+
+closure_proto_library(
+    name = "add_and_strip_prefix_closure_proto",
+    deps = [
+        ":add_and_strip_prefix_proto",
+    ],
+)
+
+proto_library(
+    name = "no_prefix_proto",
+    srcs = [
+        "no_prefix.proto",
+    ],
+)
+
+closure_proto_library(
+    name = "no_prefix_closure_proto",
+    deps = [
+        ":no_prefix_proto",
+    ],
+)
+
+proto_library(
+    name = "strip_prefix_proto",
+    srcs = [
+        "import_prefix/strip_prefix.proto",
+    ],
+    strip_import_prefix = "import_prefix",
+)
+
+closure_proto_library(
+    name = "strip_prefix_closure_proto",
+    deps = [
+        ":strip_prefix_proto",
+    ],
+)
+
+proto_library(
+    name = "import_all_proto",
+    srcs = [
+        "import_all.proto",
+    ],
+    deps = [
+        ":add_and_strip_prefix_proto",
+        ":add_prefix_proto",
+        ":no_prefix_proto",
+        ":strip_prefix_proto",
+    ],
+)
+
+closure_proto_library(
+    name = "import_all_closure_proto",
+    tags = ["manual"],
+    deps = [
+        ":import_all_proto",
+    ],
+)
 
 proto_library(
     name = "foo_proto",
@@ -51,7 +135,8 @@ closure_js_test(
     ],
     deps = [
         ":foo",
-        "//closure/library:testing",
+        ":import_all_closure_proto",
+        "//closure/library/testing:testsuite",
     ],
 )
 
@@ -94,6 +179,6 @@ closure_js_test(
     deps = [
         ":baz",
         ":foo",
-        "//closure/library:testing",
+        "//closure/library/testing:testsuite",
     ],
 )
diff --git a/closure/protobuf/test/add_prefix.proto b/closure/protobuf/test/add_prefix.proto
new file mode 100644
index 0000000000..1e9176f798
--- /dev/null
+++ b/closure/protobuf/test/add_prefix.proto
@@ -0,0 +1,21 @@
+// Copyright 2018 The Closure Rules Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+
+package io.bazel.rules.closure.protobuf.foo;
+
+message AddPrefix {
+  string foo = 1;
+}
diff --git a/closure/protobuf/test/baz_test.js b/closure/protobuf/test/baz_test.js
index 4da6da34da..2b8cdbcfeb 100644
--- a/closure/protobuf/test/baz_test.js
+++ b/closure/protobuf/test/baz_test.js
@@ -31,7 +31,6 @@ class BazTest {
 
   /** @return {void} */
   testFooField() {
-    // This test verifies that we 
     const foo = new Foo('value');
     assertEquals('value', foo.field());
   }
diff --git a/closure/protobuf/test/foo_test.js b/closure/protobuf/test/foo_test.js
index e842cff690..356994e0ee 100644
--- a/closure/protobuf/test/foo_test.js
+++ b/closure/protobuf/test/foo_test.js
@@ -16,18 +16,21 @@ goog.module('io.bazel.rules.closure.protobuf.FooTest');
 goog.setTestOnly('io.bazel.rules.closure.protobuf.FooTest');
 
 const Foo = goog.require('io.bazel.rules.closure.protobuf.Foo');
+const ImportAll = goog.require('proto.io.bazel.rules.closure.protobuf.ImportAll');
 const testSuite = goog.require('goog.testing.testSuite');
 
 
 
 class FooTest {
-  /**
-   * @return {void}
-   * @suppress {visibility}
-   */
+  /** @return {void} */
   testField() {
     const foo = new Foo('value');
     assertEquals('value', foo.field());
   }
+
+  /** @return {void} */
+  testImportAll() {
+    assertNotNull(new ImportAll());
+  }
 }
 testSuite(new FooTest());
diff --git a/closure/protobuf/test/import_all.proto b/closure/protobuf/test/import_all.proto
new file mode 100644
index 0000000000..516ac97b0f
--- /dev/null
+++ b/closure/protobuf/test/import_all.proto
@@ -0,0 +1,29 @@
+// Copyright 2018 The Closure Rules Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+
+package io.bazel.rules.closure.protobuf;
+
+import "bar/add_and_strip_prefix.proto";
+import "closure/protobuf/test/no_prefix.proto";
+import "foo/closure/protobuf/test/add_prefix.proto";
+import "strip_prefix.proto";
+
+message ImportAll {
+  NoPrefix no_prefix = 1;
+  StripPrefix strip_prefix = 2;
+  bar.AddAndStripPrefix add_and_strip_prefix = 3;
+  foo.AddPrefix add_prefix = 4;
+}
diff --git a/closure/protobuf/test/import_prefix/add_and_strip_prefix.proto b/closure/protobuf/test/import_prefix/add_and_strip_prefix.proto
new file mode 100644
index 0000000000..0ac2659526
--- /dev/null
+++ b/closure/protobuf/test/import_prefix/add_and_strip_prefix.proto
@@ -0,0 +1,21 @@
+// Copyright 2018 The Closure Rules Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+
+package bar;
+
+message AddAndStripPrefix {
+  string foo = 1;
+}
diff --git a/closure/protobuf/test/import_prefix/strip_prefix.proto b/closure/protobuf/test/import_prefix/strip_prefix.proto
new file mode 100644
index 0000000000..ffb141534f
--- /dev/null
+++ b/closure/protobuf/test/import_prefix/strip_prefix.proto
@@ -0,0 +1,19 @@
+// Copyright 2018 The Closure Rules Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+
+message StripPrefix {
+  string foo = 1;
+}
diff --git a/closure/protobuf/test/no_prefix.proto b/closure/protobuf/test/no_prefix.proto
new file mode 100644
index 0000000000..87ed2ec6fc
--- /dev/null
+++ b/closure/protobuf/test/no_prefix.proto
@@ -0,0 +1,21 @@
+// Copyright 2018 The Closure Rules Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+
+package io.bazel.rules.closure.protobuf;
+
+message NoPrefix {
+  string foo = 1;
+}
diff --git a/closure/repositories.bzl b/closure/repositories.bzl
index 3e459520f3..df985a47ee 100644
--- a/closure/repositories.bzl
+++ b/closure/repositories.bzl
@@ -22,6 +22,7 @@ def closure_repositories(
         omit_aopalliance = False,
         omit_args4j = False,
         omit_bazel_skylib = False,
+        omit_build_bazel_rules_proto = False,
         omit_clang = False,
         omit_com_google_auto_common = False,
         omit_com_google_auto_factory = False,
@@ -79,6 +80,8 @@ def closure_repositories(
         args4j()
     if not omit_bazel_skylib:
         bazel_skylib()
+    if not omit_build_bazel_rules_proto:
+        build_bazel_rules_proto()
     if not omit_clang:
         clang()
     if not omit_com_google_auto_common:
@@ -207,6 +210,14 @@ def bazel_skylib():
         urls = ["https://github.com/bazelbuild/bazel-skylib/archive/2169ae1c374aab4a09aa90e65efe1a3aad4e279b.tar.gz"],
     )
 
+def build_bazel_rules_proto():
+    http_archive(
+        name = "build_bazel_rules_proto",
+        sha256 = "26ef80422c978cd0590734c103bc66dae6932989542845efb365fcc48b6d810f",
+        strip_prefix = "rules_proto-6b247dbf28aa3b6f485047c938731ec8c2453a83",
+        urls = ["https://github.com/Yannic/rules_proto/archive/6b247dbf28aa3b6f485047c938731ec8c2453a83.tar.gz"],
+    )
+
 def clang():
     platform_http_file(
         name = "clang",
diff --git a/closure/toolchains.bzl b/closure/toolchains.bzl
new file mode 100644
index 0000000000..b03c9c7d68
--- /dev/null
+++ b/closure/toolchains.bzl
@@ -0,0 +1,20 @@
+# Copyright 2019 The Closure Rules Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Toolchains for Closure Rules."""
+
+load("@build_bazel_rules_proto//proto:workspace.bzl", "proto_register_toolchains")
+
+def closure_register_toolchains():
+    proto_register_toolchains()