diff --git a/pkg/dtd/test/file_system_service_test.dart b/pkg/dtd/test/file_system_service_test.dart
index 6ab40a78582f..ac790bebe66f 100644
--- a/pkg/dtd/test/file_system_service_test.dart
+++ b/pkg/dtd/test/file_system_service_test.dart
@@ -366,6 +366,38 @@ void main() {
             throwsAnRpcError(RpcErrorCodes.kExpectsUriParamWithFileScheme),
           );
         });
+
+        group(
+          'windows paths',
+          () {
+            // Test paths in various formats. We will test all combinations of
+            // these both as the set roots and the readFile path to ensure the
+            // calling client doesn't need to use the same escaping as the
+            // editor.
+            final roots = [
+              Uri.parse('file:///C:/foo'),
+              Uri.parse('file:///C%3A/foo'),
+              Uri.parse('file:///c:/foo'),
+            ];
+            final files = roots
+                .map((uri) => uri.replace(path: '${uri.path}/file.txt'))
+                .toList();
+
+            for (final root in roots) {
+              for (final file in files) {
+                test('can read $file in $root', () async {
+                  await client.setIDEWorkspaceRoots(dtdSecret, [root]);
+                  expect(
+                    () => client.readFileAsString(file),
+                    // Expect file does not exist (NOT a permission error).
+                    throwsAnRpcError(RpcErrorCodes.kFileDoesNotExist),
+                  );
+                });
+              }
+            }
+          },
+          skip: !Platform.isWindows,
+        );
       });
 
       group('writeFileAsString', () {
@@ -438,13 +470,13 @@ void main() {
           params: {
             'secret': dtdSecret,
             'roots': [
-              'file://$relativePath',
+              Uri.file(relativePath).toString(),
             ],
           },
         );
         final roots = await client.getIDEWorkspaceRoots();
         expect(
-          roots.ideWorkspaceRoots.map((e) => e.path),
+          roots.ideWorkspaceRoots.map((e) => e.toFilePath()),
           [simplifiedPath],
         );
       });
@@ -542,8 +574,8 @@ void main() {
         expect(listResult.result, {
           'type': 'UriList',
           'uris': containsAll([
-            'file://${fooDirectory.uri.toFilePath()}C/pubspec.yaml',
-            'file://${fooDirectory.uri.toFilePath()}C/d.txt',
+            '${fooDirectory.uri}C/pubspec.yaml',
+            '${fooDirectory.uri}C/d.txt',
           ]),
         });
       });
diff --git a/pkg/dtd_impl/lib/src/service/file_system_service.dart b/pkg/dtd_impl/lib/src/service/file_system_service.dart
index 6cd9eb6f918f..c76d18639c73 100644
--- a/pkg/dtd_impl/lib/src/service/file_system_service.dart
+++ b/pkg/dtd_impl/lib/src/service/file_system_service.dart
@@ -66,11 +66,13 @@ class FileSystemService extends InternalService {
   void _ensureIDEWorkspaceRootsContainUri(Uri uri) {
     // If in unrestricted mode, no need to do these checks.
     if (unrestrictedMode) return;
-    if (_ideWorkspaceRoots.any(
-      (root) =>
-          path.isWithin(root.path, uri.path) ||
-          path.equals(root.path, uri.path),
-    )) {
+
+    final requestedPath = uri.toFilePath();
+    if (_ideWorkspaceRoots.any((root) {
+      final rootPath = root.toFilePath();
+      return path.isWithin(rootPath, requestedPath) ||
+          path.equals(rootPath, requestedPath);
+    })) {
       return;
     }