diff --git a/pkg/apis/core/validation/events.go b/pkg/apis/core/validation/events.go
index eeecac218e5..d2578f229e0 100644
--- a/pkg/apis/core/validation/events.go
+++ b/pkg/apis/core/validation/events.go
@@ -95,7 +95,18 @@ func ValidateEventUpdate(newEvent, oldEvent *core.Event, requestVersion schema.G
 	allErrs = append(allErrs, ValidateImmutableField(newEvent.Count, oldEvent.Count, field.NewPath("count"))...)
 	allErrs = append(allErrs, ValidateImmutableField(newEvent.Reason, oldEvent.Reason, field.NewPath("reason"))...)
 	allErrs = append(allErrs, ValidateImmutableField(newEvent.Type, oldEvent.Type, field.NewPath("type"))...)
-	allErrs = append(allErrs, ValidateImmutableField(newEvent.EventTime, oldEvent.EventTime, field.NewPath("eventTime"))...)
+
+	// Disallow changes to eventTime greater than microsecond-level precision.
+	// Tolerating sub-microsecond changes is required to tolerate updates
+	// from clients that correctly truncate to microsecond-precision when serializing,
+	// or from clients built with incorrect nanosecond-precision protobuf serialization.
+	// See https://github.com/kubernetes/kubernetes/issues/111928
+	newTruncated := newEvent.EventTime.Truncate(time.Microsecond).UTC()
+	oldTruncated := oldEvent.EventTime.Truncate(time.Microsecond).UTC()
+	if newTruncated != oldTruncated {
+		allErrs = append(allErrs, ValidateImmutableField(newEvent.EventTime, oldEvent.EventTime, field.NewPath("eventTime"))...)
+	}
+
 	allErrs = append(allErrs, ValidateImmutableField(newEvent.Action, oldEvent.Action, field.NewPath("action"))...)
 	allErrs = append(allErrs, ValidateImmutableField(newEvent.Related, oldEvent.Related, field.NewPath("related"))...)
 	allErrs = append(allErrs, ValidateImmutableField(newEvent.ReportingController, oldEvent.ReportingController, field.NewPath("reportingController"))...)
diff --git a/pkg/apis/core/validation/events_test.go b/pkg/apis/core/validation/events_test.go
index e9a2f69c316..66427b65b08 100644
--- a/pkg/apis/core/validation/events_test.go
+++ b/pkg/apis/core/validation/events_test.go
@@ -20,7 +20,7 @@ import (
 	"testing"
 	"time"
 
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	eventsv1 "k8s.io/api/events/v1"
 	eventsv1beta1 "k8s.io/api/events/v1beta1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -1312,3 +1312,67 @@ func TestValidateEventUpdateForNewV1Events(t *testing.T) {
 		}
 	}
 }
+
+func TestEventV1EventTimeImmutability(t *testing.T) {
+	testcases := []struct {
+		Name  string
+		Old   metav1.MicroTime
+		New   metav1.MicroTime
+		Valid bool
+	}{
+		{
+			Name:  "noop microsecond precision",
+			Old:   metav1.NewMicroTime(time.Unix(100, int64(5*time.Microsecond))),
+			New:   metav1.NewMicroTime(time.Unix(100, int64(5*time.Microsecond))),
+			Valid: true,
+		},
+		{
+			Name:  "noop nanosecond precision",
+			Old:   metav1.NewMicroTime(time.Unix(100, int64(5*time.Nanosecond))),
+			New:   metav1.NewMicroTime(time.Unix(100, int64(5*time.Nanosecond))),
+			Valid: true,
+		},
+		{
+			Name:  "modify nanoseconds within the same microsecond",
+			Old:   metav1.NewMicroTime(time.Unix(100, int64(5*time.Nanosecond))),
+			New:   metav1.NewMicroTime(time.Unix(100, int64(6*time.Nanosecond))),
+			Valid: true,
+		},
+		{
+			Name:  "modify microseconds",
+			Old:   metav1.NewMicroTime(time.Unix(100, int64(5*time.Microsecond))),
+			New:   metav1.NewMicroTime(time.Unix(100, int64(5*time.Microsecond-time.Nanosecond))),
+			Valid: false,
+		},
+		{
+			Name:  "modify seconds",
+			Old:   metav1.NewMicroTime(time.Unix(100, 0)),
+			New:   metav1.NewMicroTime(time.Unix(101, 0)),
+			Valid: false,
+		},
+	}
+
+	for _, tc := range testcases {
+		t.Run(tc.Name, func(t *testing.T) {
+			oldEvent := &core.Event{
+				ObjectMeta:          metav1.ObjectMeta{Name: "test", Namespace: metav1.NamespaceSystem, ResourceVersion: "2"},
+				InvolvedObject:      core.ObjectReference{APIVersion: "v2", Kind: "Node"},
+				Series:              &core.EventSeries{Count: 2, LastObservedTime: tc.Old},
+				EventTime:           tc.Old,
+				ReportingController: "k8s.io/my-controller",
+				ReportingInstance:   "node-xyz",
+				Action:              "Do",
+				Reason:              "Yeees",
+				Type:                "Normal",
+			}
+
+			newEvent := oldEvent.DeepCopy()
+			newEvent.EventTime = tc.New
+
+			updateErrs := ValidateEventUpdate(newEvent, oldEvent, eventsv1.SchemeGroupVersion)
+			if e, a := tc.Valid, len(updateErrs) == 0; e != a {
+				t.Errorf("%v: expected valid=%v, got %v: %v", tc.Valid, e, a, updateErrs)
+			}
+		})
+	}
+}