diff --git a/flaml/automl/model.py b/flaml/automl/model.py
index 65ff77199..b74137cf6 100644
--- a/flaml/automl/model.py
+++ b/flaml/automl/model.py
@@ -1196,16 +1196,31 @@ class TransformersEstimator(BaseEstimator):
                     control.should_save = True
                     control.should_evaluate = True
 
-        self._trainer = TrainerForAuto(
-            args=self._training_args,
-            model_init=self._model_init,
-            train_dataset=train_dataset,
-            eval_dataset=eval_dataset,
-            tokenizer=self.tokenizer,
-            data_collator=self.data_collator,
-            compute_metrics=self._compute_metrics_by_dataset_name,
-            callbacks=[EarlyStoppingCallbackForAuto],
-        )
+        # Use processing_class for transformers >= 4.44.0, tokenizer for older versions
+        trainer_kwargs = {
+            "args": self._training_args,
+            "model_init": self._model_init,
+            "train_dataset": train_dataset,
+            "eval_dataset": eval_dataset,
+            "data_collator": self.data_collator,
+            "compute_metrics": self._compute_metrics_by_dataset_name,
+            "callbacks": [EarlyStoppingCallbackForAuto],
+        }
+
+        # Check if processing_class parameter is supported (transformers >= 4.44.0)
+        try:
+            import transformers
+            from packaging import version
+
+            if version.parse(transformers.__version__) >= version.parse("4.44.0"):
+                trainer_kwargs["processing_class"] = self.tokenizer
+            else:
+                trainer_kwargs["tokenizer"] = self.tokenizer
+        except (ImportError, AttributeError, ValueError):
+            # Fallback to tokenizer if version check fails
+            trainer_kwargs["tokenizer"] = self.tokenizer
+
+        self._trainer = TrainerForAuto(**trainer_kwargs)
 
         if self._task in NLG_TASKS:
             setattr(self._trainer, "_is_seq2seq", True)
diff --git a/flaml/automl/nlp/huggingface/utils.py b/flaml/automl/nlp/huggingface/utils.py
index 17e601a8f..0d04cfa29 100644
--- a/flaml/automl/nlp/huggingface/utils.py
+++ b/flaml/automl/nlp/huggingface/utils.py
@@ -211,29 +211,28 @@ def tokenize_onedataframe(
     hf_args=None,
     prefix_str=None,
 ):
-    with tokenizer.as_target_tokenizer():
-        _, tokenized_column_names = tokenize_row(
-            dict(X.iloc[0]),
+    _, tokenized_column_names = tokenize_row(
+        dict(X.iloc[0]),
+        tokenizer,
+        prefix=(prefix_str,) if task is SUMMARIZATION else None,
+        task=task,
+        hf_args=hf_args,
+        return_column_name=True,
+    )
+    d = X.apply(
+        lambda x: tokenize_row(
+            x,
             tokenizer,
             prefix=(prefix_str,) if task is SUMMARIZATION else None,
             task=task,
             hf_args=hf_args,
-            return_column_name=True,
-        )
-        d = X.apply(
-            lambda x: tokenize_row(
-                x,
-                tokenizer,
-                prefix=(prefix_str,) if task is SUMMARIZATION else None,
-                task=task,
-                hf_args=hf_args,
-            ),
-            axis=1,
-            result_type="expand",
-        )
-        X_tokenized = pd.DataFrame(columns=tokenized_column_names)
-        X_tokenized[tokenized_column_names] = d
-        return X_tokenized
+        ),
+        axis=1,
+        result_type="expand",
+    )
+    X_tokenized = pd.DataFrame(columns=tokenized_column_names)
+    X_tokenized[tokenized_column_names] = d
+    return X_tokenized
 
 
 def tokenize_row(