diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4f6a633e8..08582e5b6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -73,6 +73,7 @@ All-about-optimizations:
   - openvino: optimize recompile checks and lora loading
   - log: ansi color handling
   - compile: keep model compiled state
+  - prompt: cache checks when cfg changes
 
 ## Update for 2026-08-26
 
diff --git a/modules/sd_hijack_te.py b/modules/sd_hijack_te.py
index 06826cd33..ccb6c7eec 100644
--- a/modules/sd_hijack_te.py
+++ b/modules/sd_hijack_te.py
@@ -11,29 +11,39 @@ class PromptCache:
         self.id = None
         self.max = 16
 
-    def get(self, prompt):
+    @staticmethod
+    def _hashable(val):
+        if isinstance(val, list):
+            return tuple(val)
+        return val
+
+    def get(self, prompt, negative_prompt=None, cfg_enabled=None):
         if self.id != id(shared.sd_model):
             self.cache.clear()
             self.id = id(shared.sd_model)
             log.debug(f'Encode: prompt cache activate id={self.id} depth={len(self.cache)}')
+        prompt = self._hashable(prompt)
+        negative_prompt = self._hashable(negative_prompt)
         if (isinstance(prompt, list) and len(prompt) == 1 and isinstance(prompt[0], str)):
-            cached = self.cache.get(prompt[0], None)
+            cached = self.cache.get((prompt[0], negative_prompt, cfg_enabled), None)
         elif isinstance(prompt, str):
-            cached = self.cache.get(prompt, None)
+            cached = self.cache.get((prompt, negative_prompt, cfg_enabled), None)
         else:
             cached = None
         if cached:
             log.debug(f'Encode: prompt="{prompt}" cache={len(self.cache)} hit')
         return cached
 
-    def set(self, prompt, encoded):
+    def set(self, prompt, encoded, negative_prompt=None, cfg_enabled=None):
         if len(self.cache) >= self.max:
             oldest_key = next(iter(self.cache))
             del self.cache[oldest_key]
+        prompt = self._hashable(prompt)
+        negative_prompt = self._hashable(negative_prompt)
         if (isinstance(prompt, list) and len(prompt) == 1 and isinstance(prompt[0], str)):
-            self.cache[prompt[0]] = encoded
+            self.cache[(prompt[0], negative_prompt, cfg_enabled)] = encoded
         elif isinstance(prompt, str):
-            self.cache[prompt] = encoded
+            self.cache[(prompt, negative_prompt, cfg_enabled)] = encoded
 
 
 prompt_cache = PromptCache()
@@ -61,7 +71,10 @@ def hijack_encode_prompt(*args, **kwargs):
             if patch_prompt:
                 args_copy[0] = res
 
-        cached = prompt_cache.get(prompt)
+        # cache key must include cfg-affecting kwargs since encode_prompt output (e.g. negative_prompt_embeds) depends on them
+        negative_prompt = kwargs.get('negative_prompt', None)
+        cfg_enabled = kwargs.get('do_classifier_free_guidance', None)
+        cached = prompt_cache.get(prompt, negative_prompt, cfg_enabled)
         if cached is not None:
             res = cached
         else:
@@ -71,7 +84,7 @@ def hijack_encode_prompt(*args, **kwargs):
                     res = shared.sd_model.orig_encode_prompt(*args_copy, **kwargs)
                 else:
                     res = shared.sd_model.encode_prompt(*args_copy, **kwargs)
-            prompt_cache.set(prompt, res)
+            prompt_cache.set(prompt, res, negative_prompt, cfg_enabled)
 
         if hasattr(shared.sd_model, 'after_prompt_encode'):
             log.debug(f'Encode: prompt="{prompt}" op=after')