diff --git a/llmfoundry/models/mpt/modeling_mpt.py b/llmfoundry/models/mpt/modeling_mpt.py
index d6b23c04d0..34b8992d3e 100644
--- a/llmfoundry/models/mpt/modeling_mpt.py
+++ b/llmfoundry/models/mpt/modeling_mpt.py
@@ -739,6 +739,12 @@ def fsdp_wrap_fn(self, module: nn.Module) -> bool:
     def activation_checkpointing_fn(self, module: nn.Module) -> bool:
         act_ckpt_list = getattr(self.config, 'activation_checkpointing_target',
                                 None) or ['MPTBlock']
+        if isinstance(act_ckpt_list, str):
+            act_ckpt_list = [act_ckpt_list]
+        elif not isinstance(act_ckpt_list, list):
+            raise ValueError(
+                f'activation_checkpointing_target must be either a single string or a list, but got {type(act_ckpt_list)}'
+            )
 
         if 'MPTBlock' in act_ckpt_list or 'mptblock' in act_ckpt_list:
             if len(act_ckpt_list) > 1:
diff --git a/tests/test_fsdp_act_checkpoint.py b/tests/test_fsdp_act_checkpoint.py
index 3b9a746708..a7e41a3fc2 100644
--- a/tests/test_fsdp_act_checkpoint.py
+++ b/tests/test_fsdp_act_checkpoint.py
@@ -1,6 +1,8 @@
 # Copyright 2022 MosaicML LLM Foundry authors
 # SPDX-License-Identifier: Apache-2.0
 
+from typing import Union
+
 import pytest
 from composer import Trainer
 from composer.utils import get_device, using_torch_2
@@ -14,11 +16,12 @@
 @pytest.mark.world_size(2)
 @pytest.mark.gpu
 @pytest.mark.parametrize('activation_checkpointing', [True, False])
-@pytest.mark.parametrize(
-    'activation_checkpointing_target',
-    [[], ['grouped_query_attention'], ['mptblock', 'grouped_query_attention']])
+@pytest.mark.parametrize('activation_checkpointing_target', [
+    'grouped_query_attention', [], ['grouped_query_attention'],
+    ['mptblock', 'grouped_query_attention']
+])
 def test_fsdp_act_checkpoint(activation_checkpointing: bool,
-                             activation_checkpointing_target: list):
+                             activation_checkpointing_target: Union[list, str]):
     device = get_device('gpu')
     model_cfg = {
         'name': 'mpt_causal_lm',
@@ -66,7 +69,9 @@ def test_fsdp_act_checkpoint(activation_checkpointing: bool,
             module = trainer.state.model.model._fsdp_wrapped_module.transformer.blocks[
                 0]._fsdp_wrapped_module._fpw_module
         assert isinstance(module, CheckpointWrapper)
-    elif activation_checkpointing_target == ['grouped_query_attention']:
+    elif activation_checkpointing_target == [
+            'grouped_query_attention'
+    ] or activation_checkpointing_target == 'grouped_query_attention':
         assert isinstance(
             trainer.state.model.model._fsdp_wrapped_module.transformer.
             blocks[0]._fsdp_wrapped_module.attn, CheckpointWrapper)