diff --git a/invokeai/app/invocations/compel.py b/invokeai/app/invocations/compel.py
index 303e0a0c84..a5a9701149 100644
--- a/invokeai/app/invocations/compel.py
+++ b/invokeai/app/invocations/compel.py
@@ -100,7 +100,7 @@ class CompelInvocation(BaseInvocation):
                 text_encoder=text_encoder,
                 textual_inversion_manager=ti_manager,
                 dtype_for_device_getter=torch_dtype,
-                truncate_long_prompts=True,  # TODO:
+                truncate_long_prompts=False,
             )
 
             conjunction = Compel.parse_prompt_string(self.prompt)
@@ -112,9 +112,6 @@ class CompelInvocation(BaseInvocation):
             c, options = compel.build_conditioning_tensor_for_prompt_object(
                 prompt)
 
-            # TODO: long prompt support
-            # if not self.truncate_long_prompts:
-            #    [c, uc] = compel.pad_conditioning_tensors_to_same_length([c, uc])
             ec = InvokeAIDiffuserComponent.ExtraConditioningInfo(
                 tokens_count_including_eos_bos=get_max_token_count(
                     tokenizer, conjunction),
diff --git a/invokeai/backend/stable_diffusion/diffusion/shared_invokeai_diffusion.py b/invokeai/backend/stable_diffusion/diffusion/shared_invokeai_diffusion.py
index 1175475bba..307e949ef8 100644
--- a/invokeai/backend/stable_diffusion/diffusion/shared_invokeai_diffusion.py
+++ b/invokeai/backend/stable_diffusion/diffusion/shared_invokeai_diffusion.py
@@ -241,11 +241,45 @@ class InvokeAIDiffuserComponent:
 
     def _apply_standard_conditioning(self, x, sigma, unconditioning, conditioning, **kwargs):
         # fast batched path
+
+        def _pad_conditioning(cond, target_len, encoder_attention_mask):
+            conditioning_attention_mask = torch.ones((cond.shape[0], cond.shape[1]), device=cond.device, dtype=cond.dtype)
+
+            if cond.shape[1] < max_len:
+                conditioning_attention_mask = torch.cat([
+                    conditioning_attention_mask,
+                    torch.zeros((cond.shape[0], max_len - cond.shape[1]), device=cond.device, dtype=cond.dtype),
+                ], dim=1)
+
+                cond = torch.cat([
+                    cond,
+                    torch.zeros((cond.shape[0], max_len - cond.shape[1], cond.shape[2]), device=cond.device, dtype=cond.dtype),
+                ], dim=1)
+
+            if encoder_attention_mask is None:
+                encoder_attention_mask = conditioning_attention_mask
+            else:
+                encoder_attention_mask = torch.cat([
+                    encoder_attention_mask,
+                    conditioning_attention_mask,
+                ])
+            
+            return cond, encoder_attention_mask
+
         x_twice = torch.cat([x] * 2)
         sigma_twice = torch.cat([sigma] * 2)
+
+        encoder_attention_mask = None
+        if unconditioning.shape[1] != conditioning.shape[1]:
+            max_len = max(unconditioning.shape[1], conditioning.shape[1])
+            unconditioning, encoder_attention_mask = _pad_conditioning(unconditioning, max_len, encoder_attention_mask)
+            conditioning, encoder_attention_mask = _pad_conditioning(conditioning, max_len, encoder_attention_mask)
+
         both_conditionings = torch.cat([unconditioning, conditioning])
         both_results = self.model_forward_callback(
-            x_twice, sigma_twice, both_conditionings, **kwargs,
+            x_twice, sigma_twice, both_conditionings,
+            encoder_attention_mask=encoder_attention_mask,
+            **kwargs,
         )
         unconditioned_next_x, conditioned_next_x = both_results.chunk(2)
         return unconditioned_next_x, conditioned_next_x