diff --git a/docs/spark_expressions_support.md b/docs/spark_expressions_support.md
index 9d9e8f7017..086b5ff7fc 100644
--- a/docs/spark_expressions_support.md
+++ b/docs/spark_expressions_support.md
@@ -275,7 +275,7 @@
 - [x] map_contains_key
 - [ ] map_entries
 - [ ] map_from_arrays
-- [ ] map_from_entries
+- [x] map_from_entries
 - [x] map_keys
 - [ ] map_values
 - [ ] str_to_map
diff --git a/spark/src/main/scala/org/apache/comet/serde/maps.scala b/spark/src/main/scala/org/apache/comet/serde/maps.scala
index ceafc157c4..637c6eeb73 100644
--- a/spark/src/main/scala/org/apache/comet/serde/maps.scala
+++ b/spark/src/main/scala/org/apache/comet/serde/maps.scala
@@ -20,6 +20,7 @@
 package org.apache.comet.serde
 
 import org.apache.spark.sql.catalyst.expressions._
+import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.types._
 
 import org.apache.comet.serde.QueryPlanSerde.{createBinaryExpr, exprToProtoInternal, optExprWithInfo, scalarFunctionExprToProto}
@@ -136,6 +137,8 @@ object CometMapContainsKey extends CometExpressionSerde[MapContainsKey] {
 object CometMapFromEntries extends CometScalarFunction[MapFromEntries]("map_from_entries") {
   val keyUnsupportedReason = "Using BinaryType as Map keys is not allowed in map_from_entries"
   val valueUnsupportedReason = "Using BinaryType as Map values is not allowed in map_from_entries"
+  val lastWinUnsupportedReason =
+    "spark.sql.mapKeyDedupPolicy=LAST_WIN is not yet supported natively for map_from_entries"
 
   private def containsBinary(dataType: DataType): Boolean = {
     dataType match {
@@ -153,6 +156,11 @@ object CometMapFromEntries extends CometScalarFunction[MapFromEntries]("map_from
     if (containsBinary(expr.dataType.valueType)) {
       return Incompatible(Some(valueUnsupportedReason))
     }
+    // Only the default EXCEPTION policy is supported natively; fall back otherwise.
+    if (!SQLConf.get.getConfString("spark.sql.mapKeyDedupPolicy", "EXCEPTION")
+        .equalsIgnoreCase("EXCEPTION")) {
+      return Incompatible(Some(lastWinUnsupportedReason))
+    }
     Compatible(None)
   }
 }
diff --git a/spark/src/test/scala/org/apache/comet/CometMapExpressionSuite.scala b/spark/src/test/scala/org/apache/comet/CometMapExpressionSuite.scala
index 03db26e566..4fd2829ecf 100644
--- a/spark/src/test/scala/org/apache/comet/CometMapExpressionSuite.scala
+++ b/spark/src/test/scala/org/apache/comet/CometMapExpressionSuite.scala
@@ -22,6 +22,7 @@ package org.apache.comet
 import scala.util.Random
 
 import org.apache.hadoop.fs.Path
+import org.apache.spark.SparkException
 import org.apache.spark.sql.CometTestBase
 import org.apache.spark.sql.functions._
 import org.apache.spark.sql.internal.SQLConf
@@ -236,4 +237,14 @@ class CometMapExpressionSuite extends CometTestBase {
     }
   }
 
+  test("map_from_entries - duplicate keys throw under default EXCEPTION policy") {
+    val df = sql("select map_from_entries(array(struct(1, 'a'), struct(1, 'b')))")
+    val ex = intercept[SparkException] {
+      df.collect()
+    }
+    assert(
+      ex.getMessage.contains("DUPLICATED_MAP_KEY"),
+      s"expected DUPLICATED_MAP_KEY error class, got: ${ex.getMessage}")
+  }
+
 }