diff --git a/aider/commands.py b/aider/commands.py
index 43e73e87b..396c960b0 100644
--- a/aider/commands.py
+++ b/aider/commands.py
@@ -221,15 +221,18 @@ class Commands:
                 yield Completion(fname, start_position=-len(partial))
 
     def glob_filtered_to_repo(self, pattern):
-        matched_files = Path(self.coder.root).glob(pattern)
-        matched_files = [fn.relative_to(self.coder.root) for fn in matched_files]
+        raw_matched_files = Path(self.coder.root).glob(pattern)
+        matched_files = []
+        for fn in raw_matched_files:
+            matched_files += expand_subdir(fn.relative_to(self.coder.root))
 
         # if repo, filter against it
         if self.coder.repo:
             git_files = self.coder.get_tracked_files()
             matched_files = [fn for fn in matched_files if str(fn) in git_files]
 
-        return list(map(str, matched_files))
+        res = list(map(str, matched_files))
+        return res
 
     def cmd_add(self, args):
         "Add matching files to the chat session using glob patterns"
@@ -238,6 +241,7 @@ class Commands:
         git_added = []
         git_files = self.coder.get_tracked_files()
 
+        all_matched_files = set()
         for word in args.split():
             matched_files = self.glob_filtered_to_repo(word)
 
@@ -253,23 +257,25 @@ class Commands:
                         (Path(self.coder.root) / word).touch()
                         matched_files = [word]
 
-            for matched_file in matched_files:
-                abs_file_path = self.coder.abs_root_path(matched_file)
+            all_matched_files.update(matched_files)
 
-                if self.coder.repo and matched_file not in git_files:
-                    self.coder.repo.git.add(abs_file_path)
-                    git_added.append(matched_file)
+        for matched_file in all_matched_files:
+            abs_file_path = self.coder.abs_root_path(matched_file)
 
-                if abs_file_path not in self.coder.abs_fnames:
-                    content = self.io.read_text(abs_file_path)
-                    if content is not None:
-                        self.coder.abs_fnames.add(abs_file_path)
-                        self.io.tool_output(f"Added {matched_file} to the chat")
-                        added_fnames.append(matched_file)
-                    else:
-                        self.io.tool_error(f"Unable to read {matched_file}")
+            if self.coder.repo and matched_file not in git_files:
+                self.coder.repo.git.add(abs_file_path)
+                git_added.append(matched_file)
+
+            if abs_file_path in self.coder.abs_fnames:
+                self.io.tool_error(f"{matched_file} is already in the chat")
+            else:
+                content = self.io.read_text(abs_file_path)
+                if content is None:
+                    self.io.tool_error(f"Unable to read {matched_file}")
                 else:
-                    self.io.tool_error(f"{matched_file} is already in the chat")
+                    self.coder.abs_fnames.add(abs_file_path)
+                    self.io.tool_output(f"Added {matched_file} to the chat")
+                    added_fnames.append(matched_file)
 
         if self.coder.repo and git_added:
             git_added = " ".join(git_added)
@@ -380,3 +386,14 @@ class Commands:
                 self.io.tool_output(f"{cmd} {description}")
             else:
                 self.io.tool_output(f"{cmd} No description available.")
+
+
+def expand_subdir(file_path):
+    file_path = Path(file_path)
+    if file_path.is_file():
+        yield file_path
+        return
+
+    for file in file_path.rglob("*"):
+        if file.is_file():
+            yield str(file)
diff --git a/tests/test_commands.py b/tests/test_commands.py
index c43826419..3590c65e5 100644
--- a/tests/test_commands.py
+++ b/tests/test_commands.py
@@ -79,6 +79,39 @@ class TestCommands(TestCase):
         # Check if no files have been added to the chat session
         self.assertEqual(len(coder.abs_fnames), 0)
 
+    def test_cmd_add_drop_directory(self):
+        # Initialize the Commands and InputOutput objects
+        io = InputOutput(pretty=False, yes=True)
+        from aider.coders import Coder
+
+        coder = Coder.create(models.GPT35, None, io, openai_api_key="deadbeef")
+        commands = Commands(io, coder)
+
+        # Create a directory and add files to it
+        os.mkdir("test_dir")
+        os.mkdir("test_dir/another_dir")
+        with open("test_dir/test_file1.txt", "w") as f:
+            f.write("Test file 1")
+        with open("test_dir/test_file2.txt", "w") as f:
+            f.write("Test file 2")
+        with open("test_dir/another_dir/test_file.txt", "w") as f:
+            f.write("Test file 3")
+
+        # Call the cmd_add method with a directory
+        commands.cmd_add("test_dir test_dir/test_file2.txt")
+
+        # Check if the files have been added to the chat session
+        self.assertIn(str(Path("test_dir/test_file1.txt").resolve()), coder.abs_fnames)
+        self.assertIn(str(Path("test_dir/test_file2.txt").resolve()), coder.abs_fnames)
+        self.assertIn(str(Path("test_dir/another_dir/test_file.txt").resolve()), coder.abs_fnames)
+
+        commands.cmd_drop("test_dir/another_dir")
+        self.assertIn(str(Path("test_dir/test_file1.txt").resolve()), coder.abs_fnames)
+        self.assertIn(str(Path("test_dir/test_file2.txt").resolve()), coder.abs_fnames)
+        self.assertNotIn(
+            str(Path("test_dir/another_dir/test_file.txt").resolve()), coder.abs_fnames
+        )
+
     def test_cmd_drop_with_glob_patterns(self):
         # Initialize the Commands and InputOutput objects
         io = InputOutput(pretty=False, yes=True)