diff --git a/core/src/main/java/org/opensearch/sql/calcite/utils/OpenSearchTypeFactory.java b/core/src/main/java/org/opensearch/sql/calcite/utils/OpenSearchTypeFactory.java
index b8ed9b6cd7e..a048d9b303b 100644
--- a/core/src/main/java/org/opensearch/sql/calcite/utils/OpenSearchTypeFactory.java
+++ b/core/src/main/java/org/opensearch/sql/calcite/utils/OpenSearchTypeFactory.java
@@ -252,6 +252,11 @@ public static ExprType convertSqlTypeNameToExprType(SqlTypeName sqlTypeName) {
           INTERVAL;
       case ARRAY -> ARRAY;
       case MAP -> STRUCT;
+      // Calcite spells a struct as ROW. convertExprTypeToRelDataType builds STRUCT as
+      // MAP<VARCHAR, ANY> since the v2 path only passes _source JSON through, so a genuine ROW —
+      // from an engine that builds a struct out of typed columns — matched nothing and fell
+      // through to UNKNOWN.
+      case ROW -> STRUCT;
       case GEOMETRY -> GEO_POINT;
       case NULL, ANY, OTHER -> UNDEFINED;
       default -> UNKNOWN;
diff --git a/core/src/test/java/org/opensearch/sql/calcite/utils/OpenSearchTypeFactoryTest.java b/core/src/test/java/org/opensearch/sql/calcite/utils/OpenSearchTypeFactoryTest.java
index 7e57aaa9bf9..8ae907e9e30 100644
--- a/core/src/test/java/org/opensearch/sql/calcite/utils/OpenSearchTypeFactoryTest.java
+++ b/core/src/test/java/org/opensearch/sql/calcite/utils/OpenSearchTypeFactoryTest.java
@@ -286,6 +286,12 @@ public void testConvertExprTypeBinaryToNullableVarbinary() {
     assertTrue(result.isNullable());
   }
 
+  @Test
+  public void testConvertRowReturnsStructExprType() {
+    assertEquals(
+        ExprCoreType.STRUCT, OpenSearchTypeFactory.convertSqlTypeNameToExprType(SqlTypeName.ROW));
+  }
+
   // ---------- convertAnalyticsEngineRelDataTypeToExprType ----------
   // UDT-aware variant for the response-schema path. Must agree with the
   // planner-internal convertRelDataTypeToExprType on every non-UDT input.