diff --git a/python/pyspark/sql/connect/readwriter.py b/python/pyspark/sql/connect/readwriter.py
index 561447a437e6d..6da2982e92c40 100644
--- a/python/pyspark/sql/connect/readwriter.py
+++ b/python/pyspark/sql/connect/readwriter.py
@@ -111,6 +111,11 @@ def schema(self, schema: Union[StructType, str]) -> "DataFrameReader":
     schema.__doc__ = PySparkDataFrameReader.schema.__doc__
 
     def option(self, key: str, value: "OptionalPrimitiveType") -> "DataFrameReader":
+        # Remove case-insensitive matches so the latest spelling and value win.
+        normalized_key = key.lower()
+        for existing_key in list(self._options):
+            if existing_key.lower() == normalized_key:
+                del self._options[existing_key]
         self._options[key] = cast(str, to_str(value))
         return self
 
diff --git a/python/pyspark/sql/tests/connect/test_connect_plan.py b/python/pyspark/sql/tests/connect/test_connect_plan.py
index 685ea3656f5cb..6069b703b72f2 100644
--- a/python/pyspark/sql/tests/connect/test_connect_plan.py
+++ b/python/pyspark/sql/tests/connect/test_connect_plan.py
@@ -772,6 +772,22 @@ def test_datasource_read(self):
         self.assertEqual(len(data_source.paths), 1)
         self.assertEqual(data_source.paths[0], "test_path")
 
+    def test_reader_options_case_insensitive(self):
+        reader = DataFrameReader(self.connect)
+        df = (
+            reader.option("versionAsOf", 0)
+            .option("versionasof", 1)
+            .option("versionAsOf", 2)
+            .table("myTable")
+        )
+        options = df._plan.to_proto(self.connect).root.read.named_table.options
+        self.assertEqual(dict(options), {"versionAsOf": "2"})
+
+        reader = DataFrameReader(self.connect)
+        df = reader.option("header", False).option("HEADER", True).load(format="csv")
+        options = df._plan.to_proto(self.connect).root.read.data_source.options
+        self.assertEqual(dict(options), {"HEADER": "true"})
+
     def test_relation_changes(self):
         reader = DataFrameReader(self.connect)
         df = reader.option("startingVersion", "1").option("endingVersion", "5").changes("myTable")