diff --git a/docs/rules/0203/required-and-optional.md b/docs/rules/0203/required-and-optional.md
deleted file mode 100644
index 9b4df4f46..000000000
--- a/docs/rules/0203/required-and-optional.md
+++ /dev/null
@@ -1,66 +0,0 @@
----
-rule:
-  aip: 203
-  name: [core, '0203', required-and-optional]
-  summary: Required fields must not use the optional keyword.
-permalink: /203/required-and-optional
-redirect_from:
-  - /0203/required-and-optional
----
-
-# Required fields
-
-This rule enforces that fields that are annotated as required do not use the
-`optional` syntax, as mandated by [AIP-203][].
-
-## Details
-
-This rule looks for fields with a `google.api.field_behavior` annotation set to
-`REQUIRED`, and complains if the field also uses the proto3 `optional` syntax.
-
-## Examples
-
-**Incorrect** code for this rule:
-
-```proto
-// Incorrect.
-message Book {
-  string name = 1;
-
-  // Fields must not be optional and required.
-  optional string title = 2 [(google.api.field_behavior) = REQUIRED];
-}
-```
-
-**Correct** code for this rule:
-
-```proto
-// Correct.
-message Book {
-  string name = 1;
-
-  string title = 2 [(google.api.field_behavior) = REQUIRED];
-}
-```
-
-## Disabling
-
-If you need to violate this rule, use a leading comment above the field.
-Remember to also include an [aip.dev/not-precedent][] comment explaining why.
-
-```proto
-message Book {
-  string name = 1;
-
-  // Required. The title of the book.
-  // (-- api-linter: core::0203::required-and-optional=disabled
-  //     aip.dev/not-precedent: We need to do this because reasons. --)
-  optional string title = 2 [(google.api.field_behavior) = REQUIRED];
-}
-```
-
-If you need to violate this rule for an entire file, place the comment at the
-top of the file.
-
-[aip-203]: https://aip.dev/203
-[aip.dev/not-precedent]: https://aip.dev/not-precedent
diff --git a/rules/aip0203/aip0203.go b/rules/aip0203/aip0203.go
index df421da08..53f43ab71 100644
--- a/rules/aip0203/aip0203.go
+++ b/rules/aip0203/aip0203.go
@@ -39,7 +39,6 @@ func AddRules(r lint.RuleRegistry) error {
 		optionalBehaviorConflict,
 		outputOnly,
 		required,
-		requiredAndOptional,
 		unorderedListRepeated,
 	)
 }
diff --git a/rules/aip0203/required_and_optional.go b/rules/aip0203/required_and_optional.go
deleted file mode 100644
index 4cabc370e..000000000
--- a/rules/aip0203/required_and_optional.go
+++ /dev/null
@@ -1,40 +0,0 @@
-// Copyright 2019 Google LLC
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package aip0203
-
-import (
-	"github.com/googleapis/api-linter/lint"
-	"github.com/googleapis/api-linter/locations"
-	"github.com/googleapis/api-linter/rules/internal/utils"
-	"github.com/jhump/protoreflect/desc"
-)
-
-var requiredAndOptional = &lint.FieldRule{
-	Name: lint.NewRuleName(203, "required-and-optional"),
-	OnlyIf: func(f *desc.FieldDescriptor) bool {
-		return utils.GetFieldBehavior(f).Contains("REQUIRED")
-	},
-	LintField: func(f *desc.FieldDescriptor) []lint.Problem {
-		if f.IsProto3Optional() {
-			return []lint.Problem{{
-				Message:    "Required fields must not use the optional keyword.",
-				Descriptor: f,
-				Location:   locations.FieldLabel(f),
-				Suggestion: "",
-			}}
-		}
-		return nil
-	},
-}
diff --git a/rules/aip0203/required_and_optional_test.go b/rules/aip0203/required_and_optional_test.go
deleted file mode 100644
index e16b3af59..000000000
--- a/rules/aip0203/required_and_optional_test.go
+++ /dev/null
@@ -1,50 +0,0 @@
-// Copyright 2019 Google LLC
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package aip0203
-
-import (
-	"testing"
-
-	"github.com/googleapis/api-linter/rules/internal/testutils"
-)
-
-func TestRequiredAndOptional(t *testing.T) {
-	req := " [(google.api.field_behavior) = REQUIRED]"
-	for _, test := range []struct {
-		name     string
-		Optional string
-		Required string
-		problems testutils.Problems
-	}{
-		{"Neither", "", "", nil},
-		{"OptionalOnly", "optional ", "", nil},
-		{"RequiredOnly", "", req, nil},
-		{"Both", "optional ", req, testutils.Problems{{Suggestion: ""}}},
-	} {
-		t.Run(test.name, func(t *testing.T) {
-			f := testutils.ParseProto3Tmpl(t, `
-				import "google/api/field_behavior.proto";
-
-				message Book {
-					{{.Optional}}int32 page_count = 1{{.Required}};
-				}
-			`, test)
-			field := f.GetMessageTypes()[0].GetFields()[0]
-			if diff := test.problems.SetDescriptor(field).Diff(requiredAndOptional.Lint(f)); diff != "" {
-				t.Errorf(diff)
-			}
-		})
-	}
-}