diff --git a/doc/changelog.rst b/doc/changelog.rst
index 72ece7b1..5f976430 100644
--- a/doc/changelog.rst
+++ b/doc/changelog.rst
@@ -75,6 +75,11 @@ General
   `AVX <https://en.wikipedia.org/wiki/Advanced_Vector_Extensions>`_ instructions on x86-64 machines, which is not
   supported by Rosetta 2. (Before this version, users only get a cryptic "Illegal instruction" message.)
 
+Bug fixes
+^^^^^^^^^
+
+- Fixed bug in ``mj_addFileVFS`` that was causing the file path to be ignored (introduced in 2.1.4).
+
 Simulate
 ^^^^^^^^
 
diff --git a/src/engine/engine_vfs.c b/src/engine/engine_vfs.c
index fa9edbc4..ff5a9559 100644
--- a/src/engine/engine_vfs.c
+++ b/src/engine/engine_vfs.c
@@ -93,7 +93,7 @@ int mj_addFileVFS(mjVFS* vfs, const char* directory, const char* filename) {
 
   // allocate and read
   int filesize = 0;
-  vfs->filedata[vfs->nfile] = mju_fileToMemory(filename, &filesize);
+  vfs->filedata[vfs->nfile] = mju_fileToMemory(fullname, &filesize);
   if (!vfs->filedata[vfs->nfile]) {
     return -1;
   }
diff --git a/test/engine/CMakeLists.txt b/test/engine/CMakeLists.txt
index c536572e..5cb8e05c 100644
--- a/test/engine/CMakeLists.txt
+++ b/test/engine/CMakeLists.txt
@@ -69,3 +69,6 @@ target_link_libraries(engine_util_solve_test fixture gmock)
 
 mujoco_test(engine_util_spatial_test)
 target_link_libraries(engine_util_spatial_test fixture gmock)
+
+mujoco_test(engine_vfs_test)
+target_link_libraries(engine_vfs_test fixture gmock)
diff --git a/test/engine/engine_vfs_test.cc b/test/engine/engine_vfs_test.cc
new file mode 100644
index 00000000..1092319b
--- /dev/null
+++ b/test/engine/engine_vfs_test.cc
@@ -0,0 +1,47 @@
+// Copyright 2021 DeepMind Technologies Limited
+//
+// 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.
+
+#include <cstddef>
+#include <string>
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <mujoco/mujoco.h>
+#include "test/fixture.h"
+
+namespace mujoco {
+namespace {
+
+using ::testing::NotNull;
+using EngineVfsTest = MujocoTest;
+
+TEST_F(EngineVfsTest, AddFileVFS) {
+  constexpr char path[] = "engine/testdata/";
+  const std::string dir = GetTestDataFilePath(path);
+  std::string file = "refsite.xml";
+
+  std::FILE* fp = std::fopen((dir + file).c_str(), "r");
+  ASSERT_THAT(fp, NotNull()) << "Input file missing.";
+  std::fclose(fp);
+
+  auto mj_vfs = std::make_unique<mjVFS>();
+  mj_defaultVFS(mj_vfs.get());
+  EXPECT_THAT(mj_addFileVFS(mj_vfs.get(), dir.c_str(), file.c_str()), 0);
+  EXPECT_THAT(mj_vfs->nfile, 1);
+  mj_deleteFileVFS(mj_vfs.get(), file.c_str());
+  mj_deleteVFS(mj_vfs.get());
+}
+
+}  // namespace
+}  // namespace mujoco