diff --git a/internal/gps/source_cache_multi.go b/internal/gps/source_cache_multi.go
new file mode 100644
index 0000000000..5ce9108d0f
--- /dev/null
+++ b/internal/gps/source_cache_multi.go
@@ -0,0 +1,120 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gps
+
+import (
+	"github.com/golang/dep/internal/gps/pkgtree"
+)
+
+// A multiCache manages two cache levels, ephemeral in-memory and persistent on-disk.
+//
+// The in-memory cache is always checked first, with the on-disk used as a fallback.
+// Values read from disk are set in-memory when an appropriate method exists.
+//
+// Set values are cached both in-memory and on-disk.
+type multiCache struct {
+	mem, disk singleSourceCache
+}
+
+func (c *multiCache) setManifestAndLock(r Revision, ai ProjectAnalyzerInfo, m Manifest, l Lock) {
+	c.mem.setManifestAndLock(r, ai, m, l)
+	c.disk.setManifestAndLock(r, ai, m, l)
+}
+
+func (c *multiCache) getManifestAndLock(r Revision, ai ProjectAnalyzerInfo) (Manifest, Lock, bool) {
+	m, l, ok := c.mem.getManifestAndLock(r, ai)
+	if ok {
+		return m, l, true
+	}
+
+	m, l, ok = c.disk.getManifestAndLock(r, ai)
+	if ok {
+		c.mem.setManifestAndLock(r, ai, m, l)
+		return m, l, true
+	}
+
+	return nil, nil, false
+}
+
+func (c *multiCache) setPackageTree(r Revision, ptree pkgtree.PackageTree) {
+	c.mem.setPackageTree(r, ptree)
+	c.disk.setPackageTree(r, ptree)
+}
+
+func (c *multiCache) getPackageTree(r Revision) (pkgtree.PackageTree, bool) {
+	ptree, ok := c.mem.getPackageTree(r)
+	if ok {
+		return ptree, true
+	}
+
+	ptree, ok = c.disk.getPackageTree(r)
+	if ok {
+		c.mem.setPackageTree(r, ptree)
+		return ptree, true
+	}
+
+	return pkgtree.PackageTree{}, false
+}
+
+func (c *multiCache) markRevisionExists(r Revision) {
+	c.mem.markRevisionExists(r)
+	c.disk.markRevisionExists(r)
+}
+
+func (c *multiCache) setVersionMap(pvs []PairedVersion) {
+	c.mem.setVersionMap(pvs)
+	c.disk.setVersionMap(pvs)
+}
+
+func (c *multiCache) getVersionsFor(rev Revision) ([]UnpairedVersion, bool) {
+	uvs, ok := c.mem.getVersionsFor(rev)
+	if ok {
+		return uvs, true
+	}
+
+	return c.disk.getVersionsFor(rev)
+}
+
+func (c *multiCache) getAllVersions() []PairedVersion {
+	pvs := c.mem.getAllVersions()
+	if pvs != nil {
+		return pvs
+	}
+
+	pvs = c.disk.getAllVersions()
+	if pvs != nil {
+		c.mem.setVersionMap(pvs)
+		return pvs
+	}
+
+	return nil
+}
+
+func (c *multiCache) getRevisionFor(uv UnpairedVersion) (Revision, bool) {
+	rev, ok := c.mem.getRevisionFor(uv)
+	if ok {
+		return rev, true
+	}
+
+	return c.disk.getRevisionFor(uv)
+}
+
+func (c *multiCache) toRevision(v Version) (Revision, bool) {
+	rev, ok := c.mem.toRevision(v)
+	if ok {
+		return rev, true
+	}
+
+	return c.disk.toRevision(v)
+}
+
+func (c *multiCache) toUnpaired(v Version) (UnpairedVersion, bool) {
+	uv, ok := c.mem.toUnpaired(v)
+	if ok {
+		return uv, true
+	}
+
+	return c.disk.toUnpaired(v)
+}
diff --git a/internal/gps/source_cache_test.go b/internal/gps/source_cache_test.go
index ed9260087b..5e12ad19db 100644
--- a/internal/gps/source_cache_test.go
+++ b/internal/gps/source_cache_test.go
@@ -31,8 +31,29 @@ func Test_singleSourceCache(t *testing.T) {
 		}
 		return bc.newSingleSourceCache(pi), bc.close
 	}
-	t.Run("bolt/open", singleSourceCacheTest{newCache: newBolt}.run)
-	t.Run("bolt/refresh", singleSourceCacheTest{newCache: newBolt, persistent: true}.run)
+	t.Run("bolt/keepOpen", singleSourceCacheTest{newCache: newBolt}.run)
+	t.Run("bolt/reOpen", singleSourceCacheTest{newCache: newBolt, persistent: true}.run)
+
+	newMulti := func(t *testing.T, cachedir, root string) (singleSourceCache, func() error) {
+		disk, close := newBolt(t, cachedir, root)
+		return &multiCache{mem: newMemoryCache(), disk: disk}, close
+	}
+	t.Run("multi/keepOpen", singleSourceCacheTest{newCache: newMulti}.run)
+	t.Run("multi/reOpen", singleSourceCacheTest{persistent: true, newCache: newMulti}.run)
+
+	t.Run("multi/keepOpen/noDisk", singleSourceCacheTest{
+		newCache: func(*testing.T, string, string) (singleSourceCache, func() error) {
+			return &multiCache{mem: newMemoryCache(), disk: discardCache{}}, func() error { return nil }
+		},
+	}.run)
+
+	t.Run("multi/reOpen/noMem", singleSourceCacheTest{
+		persistent: true,
+		newCache: func(t *testing.T, cachedir, root string) (singleSourceCache, func() error) {
+			disk, close := newBolt(t, cachedir, root)
+			return &multiCache{mem: discardCache{}, disk: disk}, close
+		},
+	}.run)
 }
 
 var testAnalyzerInfo = ProjectAnalyzerInfo{
@@ -521,3 +542,42 @@ func packageOrErrEqual(a, b pkgtree.PackageOrErr) bool {
 
 	return true
 }
+
+// discardCache discards set values and returns nothing.
+type discardCache struct{}
+
+func (discardCache) setManifestAndLock(Revision, ProjectAnalyzerInfo, Manifest, Lock) {}
+
+func (discardCache) getManifestAndLock(Revision, ProjectAnalyzerInfo) (Manifest, Lock, bool) {
+	return nil, nil, false
+}
+
+func (discardCache) setPackageTree(Revision, pkgtree.PackageTree) {}
+
+func (discardCache) getPackageTree(Revision) (pkgtree.PackageTree, bool) {
+	return pkgtree.PackageTree{}, false
+}
+
+func (discardCache) markRevisionExists(r Revision) {}
+
+func (discardCache) setVersionMap(versionList []PairedVersion) {}
+
+func (discardCache) getVersionsFor(Revision) ([]UnpairedVersion, bool) {
+	return nil, false
+}
+
+func (discardCache) getAllVersions() []PairedVersion {
+	return nil
+}
+
+func (discardCache) getRevisionFor(UnpairedVersion) (Revision, bool) {
+	return "", false
+}
+
+func (discardCache) toRevision(v Version) (Revision, bool) {
+	return "", false
+}
+
+func (discardCache) toUnpaired(v Version) (UnpairedVersion, bool) {
+	return nil, false
+}