diff --git a/src/net/http/server.go b/src/net/http/server.go
index 371c660145..0b56edf231 100644
--- a/src/net/http/server.go
+++ b/src/net/http/server.go
@@ -3683,9 +3683,7 @@ func (h *timeoutHandler) ServeHTTP(w ResponseWriter, r *Request) {
 		tw.mu.Lock()
 		defer tw.mu.Unlock()
 		dst := w.Header()
-		for k, vv := range tw.h {
-			dst[k] = vv
-		}
+		maps.Copy(dst, tw.h)
 		if !tw.wroteHeader {
 			tw.code = StatusOK
 		}
diff --git a/src/net/http/transfer.go b/src/net/http/transfer.go
index f7eef6475e..675551287f 100644
--- a/src/net/http/transfer.go
+++ b/src/net/http/transfer.go
@@ -11,6 +11,7 @@ import (
 	"fmt"
 	"internal/godebug"
 	"io"
+	"maps"
 	"net/http/httptrace"
 	"net/http/internal"
 	"net/http/internal/ascii"
@@ -954,9 +955,7 @@ func mergeSetHeader(dst *Header, src Header) {
 		*dst = src
 		return
 	}
-	for k, vv := range src {
-		(*dst)[k] = vv
-	}
+	maps.Copy(*dst, src)
 }
 
 // unreadDataSizeLocked returns the number of bytes of unread input.