diff --git a/src/diffusers/models/activations.py b/src/diffusers/models/activations.py
index e66d90040f..8b75162ba5 100644
--- a/src/diffusers/models/activations.py
+++ b/src/diffusers/models/activations.py
@@ -21,6 +21,15 @@ from ..utils import USE_PEFT_BACKEND
 from .lora import LoRACompatibleLinear
 
 
+ACTIVATION_FUNCTIONS = {
+    "swish": nn.SiLU(),
+    "silu": nn.SiLU(),
+    "mish": nn.Mish(),
+    "gelu": nn.GELU(),
+    "relu": nn.ReLU(),
+}
+
+
 def get_activation(act_fn: str) -> nn.Module:
     """Helper function to get activation function from string.
 
@@ -30,14 +39,10 @@ def get_activation(act_fn: str) -> nn.Module:
     Returns:
         nn.Module: Activation function.
     """
-    if act_fn in ["swish", "silu"]:
-        return nn.SiLU()
-    elif act_fn == "mish":
-        return nn.Mish()
-    elif act_fn == "gelu":
-        return nn.GELU()
-    elif act_fn == "relu":
-        return nn.ReLU()
+
+    act_fn = act_fn.lower()
+    if act_fn in ACTIVATION_FUNCTIONS:
+        return ACTIVATION_FUNCTIONS[act_fn]
     else:
         raise ValueError(f"Unsupported activation function: {act_fn}")