diff --git a/poetry/packages/package.py b/poetry/packages/package.py
index 680bf31f596..04854ec72af 100644
--- a/poetry/packages/package.py
+++ b/poetry/packages/package.py
@@ -163,6 +163,12 @@ def _get_author(self):  # type: () -> dict
 
         m = AUTHOR_REGEX.match(normalize("NFC", self._authors[0]))
 
+        if m is None:
+            raise ValueError(
+                "Invalid author string. Must be in the format: "
+                "John Smith <john@example.com>"
+            )
+
         name = m.group("name")
         email = m.group("email")
 
@@ -174,6 +180,12 @@ def _get_maintainer(self):  # type: () -> dict
 
         m = AUTHOR_REGEX.match(normalize("NFC", self._maintainers[0]))
 
+        if m is None:
+            raise ValueError(
+                "Invalid maintainer string. Must be in the format: "
+                "John Smith <john@example.com>"
+            )
+
         name = m.group("name")
         email = m.group("email")
 
diff --git a/tests/packages/test_package.py b/tests/packages/test_package.py
index 54221eca4c8..19226f81c3d 100644
--- a/tests/packages/test_package.py
+++ b/tests/packages/test_package.py
@@ -30,6 +30,19 @@ def test_package_authors():
     assert package.author_email is None
 
 
+def test_package_authors_invalid():
+    package = Package("foo", "0.1.0")
+
+    package.authors.insert(0, "<John Doe")
+    with pytest.raises(ValueError) as e:
+        package.author_name
+
+    assert (
+        str(e.value)
+        == "Invalid author string. Must be in the format: John Smith <john@example.com>"
+    )
+
+
 @pytest.mark.parametrize("category", ["main", "dev"])
 def test_package_add_dependency_vcs_category(category):
     package = Package("foo", "0.1.0")