diff --git a/pkg/api/validation/validation.go b/pkg/api/validation/validation.go
index 5459c6fda5e..e7783a5c8e2 100644
--- a/pkg/api/validation/validation.go
+++ b/pkg/api/validation/validation.go
@@ -1374,11 +1374,13 @@ func validateEnvVarValueFrom(ev api.EnvVar, fldPath *field.Path) field.ErrorList
 		allErrs = append(allErrs, validateSecretKeySelector(ev.ValueFrom.SecretKeyRef, fldPath.Child("secretKeyRef"))...)
 	}
 
-	if len(ev.Value) != 0 {
+	if numSources == 0 {
+		allErrs = append(allErrs, field.Invalid(fldPath, "", "must specify one of: `fieldRef`, `resourceFieldRef`, `configMapKeyRef` or `secretKeyRef`"))
+	} else if len(ev.Value) != 0 {
 		if numSources != 0 {
 			allErrs = append(allErrs, field.Invalid(fldPath, "", "may not be specified when `value` is not empty"))
 		}
-	} else if numSources != 1 {
+	} else if numSources > 1 {
 		allErrs = append(allErrs, field.Invalid(fldPath, "", "may not have more than one field specified at a time"))
 	}
 
diff --git a/pkg/api/validation/validation_test.go b/pkg/api/validation/validation_test.go
index e91ee13d64f..094a4a0d19a 100644
--- a/pkg/api/validation/validation_test.go
+++ b/pkg/api/validation/validation_test.go
@@ -2446,6 +2446,14 @@ func TestValidateEnv(t *testing.T) {
 			}},
 			expectedError: "[0].valueFrom: Invalid value: \"\": may not be specified when `value` is not empty",
 		},
+		{
+			name: "valueFrom without a source",
+			envs: []api.EnvVar{{
+				Name:      "abc",
+				ValueFrom: &api.EnvVarSource{},
+			}},
+			expectedError: "[0].valueFrom: Invalid value: \"\": must specify one of: `fieldRef`, `resourceFieldRef`, `configMapKeyRef` or `secretKeyRef`",
+		},
 		{
 			name: "valueFrom.fieldRef and valueFrom.secretKeyRef specified",
 			envs: []api.EnvVar{{