diff --git a/workflow/common/ancestry.go b/workflow/common/ancestry.go
index fb241f134b6d..e91f7aac006c 100644
--- a/workflow/common/ancestry.go
+++ b/workflow/common/ancestry.go
@@ -23,6 +23,7 @@ const (
 	TaskResultFailed       TaskResult = "Failed"
 	TaskResultErrored      TaskResult = "Errored"
 	TaskResultSkipped      TaskResult = "Skipped"
+	TaskResultOmitted      TaskResult = "Omitted"
 	TaskResultDaemoned     TaskResult = "Daemoned"
 	TaskResultAnySucceeded TaskResult = "AnySucceeded"
 	TaskResultAllFailed    TaskResult = "AllFailed"
@@ -96,7 +97,7 @@ func ValidateTaskResults(dagTask *wfv1.DAGTask) error {
 		split := strings.Split(matchGroup[1], ".")
 		taskName, taskResult := split[0], TaskResult(split[1])
 		switch taskResult {
-		case TaskResultSucceeded, TaskResultFailed, TaskResultSkipped, TaskResultErrored, TaskResultDaemoned, TaskResultAnySucceeded, TaskResultAllFailed:
+		case TaskResultSucceeded, TaskResultFailed, TaskResultSkipped, TaskResultOmitted, TaskResultErrored, TaskResultDaemoned, TaskResultAnySucceeded, TaskResultAllFailed:
 			// Do nothing
 		default:
 			return fmt.Errorf("task result '%s' for task '%s' is invalid", taskResult, taskName)
diff --git a/workflow/common/ancestry_test.go b/workflow/common/ancestry_test.go
index bded4df67e01..013f251d2a7a 100644
--- a/workflow/common/ancestry_test.go
+++ b/workflow/common/ancestry_test.go
@@ -88,6 +88,10 @@ func TestValidateTaskResults(t *testing.T) {
 	err = ValidateTaskResults(task)
 	assert.NoError(t, err)
 
+	task = &wfv1.DAGTask{Depends: "((task-1.Succeeded || task-1.Omitted) || task-2.Succeeded) && !task-3.Skipped && task-2.Failed || task-6.Succeeded"}
+	err = ValidateTaskResults(task)
+	assert.NoError(t, err)
+
 	task = &wfv1.DAGTask{Depends: "(task-1.DoeNotExist || task-2.Succeeded)"}
 	err = ValidateTaskResults(task)
 	assert.Error(t, err, "task result 'DoeNotExist' for task 'task-1' is invalid")