diff --git a/proto/substrait/algebra.proto b/proto/substrait/algebra.proto
index 3dba8ac9a..fd24c0753 100644
--- a/proto/substrait/algebra.proto
+++ b/proto/substrait/algebra.proto
@@ -631,6 +631,10 @@ message WriteRel {
   OutputMode output = 6;
   RelCommon common = 7;
 
+  // update_expressions is used with UPDATE to determine the new values for the fields in the input `Rel`.
+  // The schema of update_expressions must match `table_schema`.
+  repeated Expression update_expressions = 9;
+
   enum WriteOp {
     WRITE_OP_UNSPECIFIED = 0;
     // The insert of new records in a table