diff --git a/lib/propshaft/asset.rb b/lib/propshaft/asset.rb
index 759523f..c9cc6bd 100644
--- a/lib/propshaft/asset.rb
+++ b/lib/propshaft/asset.rb
@@ -28,7 +28,7 @@ def digested_path
     if already_digested?
       logical_path
     else
-      logical_path.sub(/\.(\w+)$/) { |ext| "-#{digest}#{ext}" }
+      logical_path.sub(/\.(\w+(\.map)?)$/) { |ext| "-#{digest}#{ext}" }
     end
   end
 
diff --git a/test/fixtures/assets/first_path/file-is-a-sourcemap.js.map b/test/fixtures/assets/first_path/file-is-a-sourcemap.js.map
new file mode 100644
index 0000000..e69de29
diff --git a/test/propshaft/asset_test.rb b/test/propshaft/asset_test.rb
index 6d27ec1..5c0749c 100644
--- a/test/propshaft/asset_test.rb
+++ b/test/propshaft/asset_test.rb
@@ -40,6 +40,9 @@ class Propshaft::AssetTest < ActiveSupport::TestCase
 
     assert_equal "file-not.digested-e206c34f.css",
       find_asset("file-not.digested.css").digested_path.to_s
+
+    assert_equal "file-is-a-sourcemap-da39a3ee.js.map",
+      find_asset("file-is-a-sourcemap.js.map").digested_path.to_s
   end
 
   test "value object equality" do
diff --git a/test/propshaft/compiler/source_mapping_urls_test.rb b/test/propshaft/compiler/source_mapping_urls_test.rb
index dc69f27..ca06d20 100644
--- a/test/propshaft/compiler/source_mapping_urls_test.rb
+++ b/test/propshaft/compiler/source_mapping_urls_test.rb
@@ -14,14 +14,14 @@ class Propshaft::Compiler::SourceMappingUrlsTest < ActiveSupport::TestCase
   end
 
   test "matching source map" do
-    assert_match %r{//# sourceMappingURL=/assets/source.js-[a-z0-9]{8}\.map},
+    assert_match %r{//# sourceMappingURL=/assets/source-[a-z0-9]{8}\.js.map},
                  compile_asset(find_asset("source.js", fixture_path: "mapped"))
-    assert_match %r{/\*# sourceMappingURL=/assets/source.css-[a-z0-9]{8}\.map},
+    assert_match %r{/\*# sourceMappingURL=/assets/source-[a-z0-9]{8}\.css.map},
                  compile_asset(find_asset("source.css", fixture_path: "mapped"))
   end
 
   test "matching nested source map" do
-    assert_match %r{//# sourceMappingURL=/assets/nested/another-source.js-[a-z0-9]{8}\.map},
+    assert_match %r{//# sourceMappingURL=/assets/nested/another-source-[a-z0-9]{8}\.js.map},
                  compile_asset(find_asset("nested/another-source.js", fixture_path: "mapped"))
   end
 
@@ -38,9 +38,9 @@ class Propshaft::Compiler::SourceMappingUrlsTest < ActiveSupport::TestCase
   end
 
   test "sourceMappingURL not at the beginning of the line, but at end of file, is processed" do
-    assert_match %r{//# sourceMappingURL=/assets/sourceMappingURL-not-at-start.js-[a-z0-9]{8}\.map},
+    assert_match %r{//# sourceMappingURL=/assets/sourceMappingURL-not-at-start-[a-z0-9]{8}\.js.map},
                  compile_asset(find_asset("sourceMappingURL-not-at-start.js", fixture_path: "mapped"))
-    assert_match %r{/\*# sourceMappingURL=/assets/sourceMappingURL-not-at-start.css-[a-z0-9]{8}\.map \*/},
+    assert_match %r{/\*# sourceMappingURL=/assets/sourceMappingURL-not-at-start-[a-z0-9]{8}\.css.map \*/},
                  compile_asset(find_asset("sourceMappingURL-not-at-start.css", fixture_path: "mapped"))
   end
 
@@ -54,9 +54,9 @@ class Propshaft::Compiler::SourceMappingUrlsTest < ActiveSupport::TestCase
   end
 
   test "sourceMapURL is already prefixed with url_prefix" do
-    assert_match %r{//# sourceMappingURL=/assets/sourceMappingURL-already-prefixed.js-[a-z0-9]{8}\.map},
+    assert_match %r{//# sourceMappingURL=/assets/sourceMappingURL-already-prefixed-[a-z0-9]{8}\.js\.map},
                  compile_asset(find_asset("sourceMappingURL-already-prefixed.js", fixture_path: "mapped"))
-    assert_match %r{//# sourceMappingURL=/assets/nested/sourceMappingURL-already-prefixed-nested.js-[a-z0-9]{8}\.map},
+    assert_match %r{//# sourceMappingURL=/assets/nested/sourceMappingURL-already-prefixed-nested-[a-z0-9]{8}\.js\.map},
                  compile_asset(find_asset("nested/sourceMappingURL-already-prefixed-nested.js", fixture_path: "mapped"))
   end
 
@@ -68,7 +68,7 @@ class Propshaft::Compiler::SourceMappingUrlsTest < ActiveSupport::TestCase
   test "relative url root" do
     @options.relative_url_root = "/url-root"
 
-    assert_match %r{//# sourceMappingURL=/url-root/assets/source.js-[a-z0-9]{8}\.map},
+    assert_match %r{//# sourceMappingURL=/url-root/assets/source-[a-z0-9]{8}\.js.map},
                   compile_asset(find_asset("source.js", fixture_path: "mapped"))
   end