diff --git a/spark/src/main/scala/org/apache/comet/serde/strings.scala b/spark/src/main/scala/org/apache/comet/serde/strings.scala
index 968fe8cd69..7d2b2c25e1 100644
--- a/spark/src/main/scala/org/apache/comet/serde/strings.scala
+++ b/spark/src/main/scala/org/apache/comet/serde/strings.scala
@@ -479,4 +479,50 @@ trait CommonStringExprs {
         None
     }
   }
+
+  def hoursOfTimeToProto(
+      expr: Expression,
+      inputs: Seq[Attribute],
+      binding: Boolean): Option[Expr] = {
+    val childOpt = expr.children.headOption.orElse {
+      withInfo(expr, "HoursOfTime has no child expression")
+      None
+    }
+
+    childOpt.flatMap { child =>
+      val timeZoneId = {
+        val exprClass = expr.getClass
+        try {
+          val timeZoneIdMethod = exprClass.getMethod("timeZoneId")
+          timeZoneIdMethod.invoke(expr).asInstanceOf[Option[String]]
+        } catch {
+          case _: NoSuchMethodException =>
+            try {
+              val timeZoneIdField = exprClass.getField("timeZoneId")
+              timeZoneIdField.get(expr).asInstanceOf[Option[String]]
+            } catch {
+              case _: NoSuchFieldException | _: SecurityException => None
+            }
+        }
+      }
+
+      exprToProtoInternal(child, inputs, binding)
+        .map { childExpr =>
+          val builder = ExprOuterClass.Hour.newBuilder()
+          builder.setChild(childExpr)
+
+          val timeZone = timeZoneId.getOrElse("UTC")
+          builder.setTimezone(timeZone)
+
+          ExprOuterClass.Expr
+            .newBuilder()
+            .setHour(builder)
+            .build()
+        }
+        .orElse {
+          withInfo(expr, child)
+          None
+        }
+    }
+  }
 }
diff --git a/spark/src/main/spark-3.4/org/apache/comet/shims/CometExprShim.scala b/spark/src/main/spark-3.4/org/apache/comet/shims/CometExprShim.scala
index f80a8909f6..5794f6e64f 100644
--- a/spark/src/main/spark-3.4/org/apache/comet/shims/CometExprShim.scala
+++ b/spark/src/main/spark-3.4/org/apache/comet/shims/CometExprShim.scala
@@ -22,9 +22,11 @@ package org.apache.comet.shims
 import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.catalyst.expressions.aggregate.Sum
 
+import org.apache.comet.CometSparkSessionExtensions.withInfo
 import org.apache.comet.expressions.CometEvalMode
 import org.apache.comet.serde.CommonStringExprs
 import org.apache.comet.serde.ExprOuterClass.{BinaryOutputStyle, Expr}
+import org.apache.comet.serde.QueryPlanSerde.exprToProtoInternal
 
 /**
  * `CometExprShim` acts as a shim for parsing expressions from different Spark versions.
@@ -44,6 +46,9 @@ trait CometExprShim extends CommonStringExprs {
         // Right child is the encoding expression.
         stringDecode(expr, s.charset, s.bin, inputs, binding)
 
+      case _ if expr.getClass.getSimpleName == "HoursOfTime" =>
+        hoursOfTimeToProto(expr, inputs, binding)
+
       case _ => None
     }
   }
diff --git a/spark/src/main/spark-3.5/org/apache/comet/shims/CometExprShim.scala b/spark/src/main/spark-3.5/org/apache/comet/shims/CometExprShim.scala
index d3e3270700..8b9b52856c 100644
--- a/spark/src/main/spark-3.5/org/apache/comet/shims/CometExprShim.scala
+++ b/spark/src/main/spark-3.5/org/apache/comet/shims/CometExprShim.scala
@@ -87,6 +87,9 @@ trait CometExprShim extends CommonStringExprs {
         val optExpr = scalarFunctionExprToProto("width_bucket", childExprs: _*)
         optExprWithInfo(optExpr, wb, wb.children: _*)
 
+      case _ if expr.getClass.getSimpleName == "HoursOfTime" =>
+        hoursOfTimeToProto(expr, inputs, binding)
+
       case _ => None
     }
   }
diff --git a/spark/src/main/spark-4.0/org/apache/comet/shims/CometExprShim.scala b/spark/src/main/spark-4.0/org/apache/comet/shims/CometExprShim.scala
index 3d5b34bfd2..0d2373225e 100644
--- a/spark/src/main/spark-4.0/org/apache/comet/shims/CometExprShim.scala
+++ b/spark/src/main/spark-4.0/org/apache/comet/shims/CometExprShim.scala
@@ -169,6 +169,26 @@ trait CometExprShim extends CommonStringExprs {
           optExprWithInfo(mapSortExpr, ms, ms.child)
         }
 
+      case h: HoursOfTime =>
+        exprToProtoInternal(h.child, inputs, binding) match {
+          case Some(childExpr) =>
+            val builder = ExprOuterClass.Hour.newBuilder()
+            builder.setChild(childExpr)
+            val timeZone = h.timeZoneId.getOrElse("UTC")
+            builder.setTimezone(timeZone)
+            Some(
+              ExprOuterClass.Expr
+                .newBuilder()
+                .setHour(builder)
+                .build())
+          case None =>
+            withInfo(h, h.child)
+            None
+        }
+
+      case _ if expr.getClass.getSimpleName == "HoursOfTime" =>
+        hoursOfTimeToProto(expr, inputs, binding)
+
       case _ => None
     }
   }
diff --git a/spark/src/test/scala/org/apache/comet/CometExpressionSuite.scala b/spark/src/test/scala/org/apache/comet/CometExpressionSuite.scala
index 92ae4b9b52..dcf3da7b1e 100644
--- a/spark/src/test/scala/org/apache/comet/CometExpressionSuite.scala
+++ b/spark/src/test/scala/org/apache/comet/CometExpressionSuite.scala
@@ -572,6 +572,23 @@ class CometExpressionSuite extends CometTestBase with AdaptiveSparkPlanHelper {
     }
   }
 
+  test("hourOfTime expression support") {
+    // This test verifies that hour() function works correctly with timestamp columns.
+    // If Spark generates HoursOfTime expression (a RuntimeReplaceable expression),
+    // it will be handled by the version-specific shim and converted to Hour proto.
+    Seq(true, false).foreach { dictionaryEnabled =>
+      withTempDir { dir =>
+        val path = new Path(dir.toURI.toString, "part-r-0.parquet")
+        makeRawTimeParquetFile(path, dictionaryEnabled = dictionaryEnabled, 10000)
+        readParquetFile(path.toString) { df =>
+          val query = df.select(expr("hour(_1)"))
+
+          checkSparkAnswerAndOperator(query)
+        }
+      }
+    }
+  }
+
   test("cast timestamp and timestamp_ntz") {
     withSQLConf(
       SESSION_LOCAL_TIMEZONE.key -> "Asia/Kathmandu",