diff --git a/src/alterschema/CMakeLists.txt b/src/alterschema/CMakeLists.txt
index 22da55e73..98c4dcf16 100644
--- a/src/alterschema/CMakeLists.txt
+++ b/src/alterschema/CMakeLists.txt
@@ -155,6 +155,7 @@ sourcemeta_library(NAMESPACE sourcemeta PROJECT blaze NAME alterschema
     linter/properties_default.h
     linter/property_names_default.h
     linter/property_names_type_default.h
+    linter/require_schema_declaration.h
     linter/simple_properties_identifiers.h
     linter/then_empty.h
     linter/title_description_equal.h
diff --git a/src/alterschema/alterschema.cc b/src/alterschema/alterschema.cc
index 9b32e78f2..681411476 100644
--- a/src/alterschema/alterschema.cc
+++ b/src/alterschema/alterschema.cc
@@ -269,6 +269,7 @@ auto WALK_UP_IN_PLACE_APPLICATORS(const JSON &root, const SchemaFrame &frame,
 #include "linter/properties_default.h"
 #include "linter/property_names_default.h"
 #include "linter/property_names_type_default.h"
+#include "linter/require_schema_declaration.h"
 #include "linter/simple_properties_identifiers.h"
 #include "linter/title_description_equal.h"
 #include "linter/title_trailing_period.h"
@@ -482,6 +483,7 @@ auto add(SchemaTransformer &bundle, const AlterSchemaMode mode) -> void {
     bundle.add<UnsatisfiableMinProperties>();
     bundle.add<EnumToConst>();
     bundle.add<ForbidEmptyEnum>();
+    bundle.add<RequireSchemaDeclaration>();
     bundle.add<TopLevelTitle>();
     bundle.add<TopLevelDescription>();
     bundle.add<TopLevelExamples>();
diff --git a/src/alterschema/linter/require_schema_declaration.h b/src/alterschema/linter/require_schema_declaration.h
new file mode 100644
index 000000000..9a7842ca8
--- /dev/null
+++ b/src/alterschema/linter/require_schema_declaration.h
@@ -0,0 +1,32 @@
+class RequireSchemaDeclaration final : public SchemaTransformRule {
+public:
+  using mutates = std::false_type;
+  using reframe_after_transform = std::false_type;
+  RequireSchemaDeclaration()
+      : SchemaTransformRule{
+            "require_schema_declaration",
+            "A schema should declare its dialect using the `$schema` "
+            "keyword"} {};
+  [[nodiscard]] auto
+  condition(const sourcemeta::core::JSON &schema,
+            const sourcemeta::core::JSON &,
+            const sourcemeta::blaze::Vocabularies &vocabularies,
+            const sourcemeta::blaze::SchemaFrame &,
+            const sourcemeta::blaze::SchemaFrame::Location &location,
+            const sourcemeta::blaze::SchemaWalker &,
+            const sourcemeta::blaze::SchemaResolver &, const bool) const
+      -> SchemaTransformRule::Result override {
+    ONLY_CONTINUE_IF(location.pointer.empty());
+    ONLY_CONTINUE_IF(vocabularies.contains_any(
+        {Vocabularies::Known::JSON_Schema_2020_12_Core,
+         Vocabularies::Known::JSON_Schema_2019_09_Core,
+         Vocabularies::Known::JSON_Schema_Draft_7,
+         Vocabularies::Known::JSON_Schema_Draft_6,
+         Vocabularies::Known::JSON_Schema_Draft_4,
+         Vocabularies::Known::JSON_Schema_Draft_3,
+         Vocabularies::Known::JSON_Schema_Draft_3_Hyper}));
+    ONLY_CONTINUE_IF(schema.is_object());
+    ONLY_CONTINUE_IF(!schema.defines("$schema"));
+    return APPLIES_TO_KEYWORDS("$schema");
+  }
+};
diff --git a/test/alterschema/alterschema_lint_2019_09_test.cc b/test/alterschema/alterschema_lint_2019_09_test.cc
index e3232b0f5..af0130b2c 100644
--- a/test/alterschema/alterschema_lint_2019_09_test.cc
+++ b/test/alterschema/alterschema_lint_2019_09_test.cc
@@ -5982,3 +5982,47 @@ TEST(AlterSchema_lint_2019_09,
   EXPECT_EQ(sourcemeta::core::to_string(outcome.locations.at(1)),
             "/patternProperties/[[:digit:]]");
 }
+
+TEST(AlterSchema_lint_2019_09, require_schema_declaration_1) {
+  const sourcemeta::core::JSON document = sourcemeta::core::parse_json(R"JSON({
+    "$schema": "https://json-schema.org/draft/2019-09/schema",
+    "title": "My Schema",
+    "description": "A schema",
+    "examples": [ "hello" ],
+    "type": "string"
+  })JSON");
+
+  LINT_WITHOUT_FIX(document, result, traces);
+
+  EXPECT_TRUE(result.first);
+  EXPECT_EQ(traces.size(), 0);
+}
+
+TEST(AlterSchema_lint_2019_09, require_schema_declaration_2) {
+  const sourcemeta::core::JSON document = sourcemeta::core::parse_json(R"JSON({
+    "title": "My Schema",
+    "description": "A schema",
+    "examples": [ "hello" ],
+    "type": "string"
+  })JSON");
+
+  std::vector<std::tuple<sourcemeta::core::Pointer, std::string, std::string,
+                         sourcemeta::blaze::SchemaTransformRule::Result, bool>>
+      traces;
+  sourcemeta::blaze::SchemaTransformer bundle;
+  sourcemeta::blaze::add(bundle, sourcemeta::blaze::AlterSchemaMode::Linter);
+  const auto result = bundle.check(
+      document, sourcemeta::blaze::schema_walker, alterschema_test_resolver,
+      [&traces](const auto &pointer, const auto &name, const auto &message,
+                const auto &outcome, const auto &fixable) {
+        traces.emplace_back(pointer, name, message, outcome, fixable);
+      },
+      "https://json-schema.org/draft/2019-09/schema");
+
+  EXPECT_FALSE(result.first);
+  EXPECT_EQ(traces.size(), 1);
+  EXPECT_LINT_TRACE(traces, 0, "", "require_schema_declaration",
+                    "A schema should declare its dialect using the `$schema` "
+                    "keyword",
+                    false);
+}
diff --git a/test/alterschema/alterschema_lint_2020_12_test.cc b/test/alterschema/alterschema_lint_2020_12_test.cc
index d40efbf56..90559222b 100644
--- a/test/alterschema/alterschema_lint_2020_12_test.cc
+++ b/test/alterschema/alterschema_lint_2020_12_test.cc
@@ -13583,3 +13583,47 @@ TEST(AlterSchema_lint_2020_12, embedded_custom_metaschema) {
 
   EXPECT_EQ(document, expected);
 }
+
+TEST(AlterSchema_lint_2020_12, require_schema_declaration_1) {
+  const sourcemeta::core::JSON document = sourcemeta::core::parse_json(R"JSON({
+    "$schema": "https://json-schema.org/draft/2020-12/schema",
+    "title": "My Schema",
+    "description": "A schema",
+    "examples": [ "hello" ],
+    "type": "string"
+  })JSON");
+
+  LINT_WITHOUT_FIX(document, result, traces);
+
+  EXPECT_TRUE(result.first);
+  EXPECT_EQ(traces.size(), 0);
+}
+
+TEST(AlterSchema_lint_2020_12, require_schema_declaration_2) {
+  const sourcemeta::core::JSON document = sourcemeta::core::parse_json(R"JSON({
+    "title": "My Schema",
+    "description": "A schema",
+    "examples": [ "hello" ],
+    "type": "string"
+  })JSON");
+
+  std::vector<std::tuple<sourcemeta::core::Pointer, std::string, std::string,
+                         sourcemeta::blaze::SchemaTransformRule::Result, bool>>
+      traces;
+  sourcemeta::blaze::SchemaTransformer bundle;
+  sourcemeta::blaze::add(bundle, sourcemeta::blaze::AlterSchemaMode::Linter);
+  const auto result = bundle.check(
+      document, sourcemeta::blaze::schema_walker, alterschema_test_resolver,
+      [&traces](const auto &pointer, const auto &name, const auto &message,
+                const auto &outcome, const auto &fixable) {
+        traces.emplace_back(pointer, name, message, outcome, fixable);
+      },
+      "https://json-schema.org/draft/2020-12/schema");
+
+  EXPECT_FALSE(result.first);
+  EXPECT_EQ(traces.size(), 1);
+  EXPECT_LINT_TRACE(traces, 0, "", "require_schema_declaration",
+                    "A schema should declare its dialect using the `$schema` "
+                    "keyword",
+                    false);
+}
diff --git a/test/alterschema/alterschema_lint_draft3_test.cc b/test/alterschema/alterschema_lint_draft3_test.cc
index 07e5802ee..512ea7a63 100644
--- a/test/alterschema/alterschema_lint_draft3_test.cc
+++ b/test/alterschema/alterschema_lint_draft3_test.cc
@@ -3436,3 +3436,45 @@ TEST(AlterSchema_lint_draft3,
   EXPECT_EQ(sourcemeta::core::to_string(outcome.locations.at(1)),
             "/patternProperties/[[:digit:]]");
 }
+
+TEST(AlterSchema_lint_draft3, require_schema_declaration_1) {
+  const sourcemeta::core::JSON document = sourcemeta::core::parse_json(R"JSON({
+    "$schema": "http://json-schema.org/draft-03/schema#",
+    "title": "My Schema",
+    "description": "A schema",
+    "type": "string"
+  })JSON");
+
+  LINT_WITHOUT_FIX(document, result, traces);
+
+  EXPECT_TRUE(result.first);
+  EXPECT_EQ(traces.size(), 0);
+}
+
+TEST(AlterSchema_lint_draft3, require_schema_declaration_2) {
+  const sourcemeta::core::JSON document = sourcemeta::core::parse_json(R"JSON({
+    "title": "My Schema",
+    "description": "A schema",
+    "type": "string"
+  })JSON");
+
+  std::vector<std::tuple<sourcemeta::core::Pointer, std::string, std::string,
+                         sourcemeta::blaze::SchemaTransformRule::Result, bool>>
+      traces;
+  sourcemeta::blaze::SchemaTransformer bundle;
+  sourcemeta::blaze::add(bundle, sourcemeta::blaze::AlterSchemaMode::Linter);
+  const auto result = bundle.check(
+      document, sourcemeta::blaze::schema_walker, alterschema_test_resolver,
+      [&traces](const auto &pointer, const auto &name, const auto &message,
+                const auto &outcome, const auto &fixable) {
+        traces.emplace_back(pointer, name, message, outcome, fixable);
+      },
+      "http://json-schema.org/draft-03/schema#");
+
+  EXPECT_FALSE(result.first);
+  EXPECT_EQ(traces.size(), 1);
+  EXPECT_LINT_TRACE(traces, 0, "", "require_schema_declaration",
+                    "A schema should declare its dialect using the `$schema` "
+                    "keyword",
+                    false);
+}
diff --git a/test/alterschema/alterschema_lint_draft4_test.cc b/test/alterschema/alterschema_lint_draft4_test.cc
index d0e9e846d..c4045e00c 100644
--- a/test/alterschema/alterschema_lint_draft4_test.cc
+++ b/test/alterschema/alterschema_lint_draft4_test.cc
@@ -3704,3 +3704,45 @@ TEST(AlterSchema_lint_draft4,
   EXPECT_EQ(sourcemeta::core::to_string(outcome.locations.at(1)),
             "/patternProperties/[[:digit:]]");
 }
+
+TEST(AlterSchema_lint_draft4, require_schema_declaration_1) {
+  const sourcemeta::core::JSON document = sourcemeta::core::parse_json(R"JSON({
+    "$schema": "http://json-schema.org/draft-04/schema#",
+    "title": "My Schema",
+    "description": "A schema",
+    "type": "string"
+  })JSON");
+
+  LINT_WITHOUT_FIX(document, result, traces);
+
+  EXPECT_TRUE(result.first);
+  EXPECT_EQ(traces.size(), 0);
+}
+
+TEST(AlterSchema_lint_draft4, require_schema_declaration_2) {
+  const sourcemeta::core::JSON document = sourcemeta::core::parse_json(R"JSON({
+    "title": "My Schema",
+    "description": "A schema",
+    "type": "string"
+  })JSON");
+
+  std::vector<std::tuple<sourcemeta::core::Pointer, std::string, std::string,
+                         sourcemeta::blaze::SchemaTransformRule::Result, bool>>
+      traces;
+  sourcemeta::blaze::SchemaTransformer bundle;
+  sourcemeta::blaze::add(bundle, sourcemeta::blaze::AlterSchemaMode::Linter);
+  const auto result = bundle.check(
+      document, sourcemeta::blaze::schema_walker, alterschema_test_resolver,
+      [&traces](const auto &pointer, const auto &name, const auto &message,
+                const auto &outcome, const auto &fixable) {
+        traces.emplace_back(pointer, name, message, outcome, fixable);
+      },
+      "http://json-schema.org/draft-04/schema#");
+
+  EXPECT_FALSE(result.first);
+  EXPECT_EQ(traces.size(), 1);
+  EXPECT_LINT_TRACE(traces, 0, "", "require_schema_declaration",
+                    "A schema should declare its dialect using the `$schema` "
+                    "keyword",
+                    false);
+}
diff --git a/test/alterschema/alterschema_lint_draft6_test.cc b/test/alterschema/alterschema_lint_draft6_test.cc
index 4a3ad83ad..7935864df 100644
--- a/test/alterschema/alterschema_lint_draft6_test.cc
+++ b/test/alterschema/alterschema_lint_draft6_test.cc
@@ -3812,3 +3812,47 @@ TEST(AlterSchema_lint_draft6,
   EXPECT_EQ(sourcemeta::core::to_string(outcome.locations.at(1)),
             "/patternProperties/[[:digit:]]");
 }
+
+TEST(AlterSchema_lint_draft6, require_schema_declaration_1) {
+  const sourcemeta::core::JSON document = sourcemeta::core::parse_json(R"JSON({
+    "$schema": "http://json-schema.org/draft-06/schema#",
+    "title": "My Schema",
+    "description": "A schema",
+    "examples": [ "hello" ],
+    "type": "string"
+  })JSON");
+
+  LINT_WITHOUT_FIX(document, result, traces);
+
+  EXPECT_TRUE(result.first);
+  EXPECT_EQ(traces.size(), 0);
+}
+
+TEST(AlterSchema_lint_draft6, require_schema_declaration_2) {
+  const sourcemeta::core::JSON document = sourcemeta::core::parse_json(R"JSON({
+    "title": "My Schema",
+    "description": "A schema",
+    "examples": [ "hello" ],
+    "type": "string"
+  })JSON");
+
+  std::vector<std::tuple<sourcemeta::core::Pointer, std::string, std::string,
+                         sourcemeta::blaze::SchemaTransformRule::Result, bool>>
+      traces;
+  sourcemeta::blaze::SchemaTransformer bundle;
+  sourcemeta::blaze::add(bundle, sourcemeta::blaze::AlterSchemaMode::Linter);
+  const auto result = bundle.check(
+      document, sourcemeta::blaze::schema_walker, alterschema_test_resolver,
+      [&traces](const auto &pointer, const auto &name, const auto &message,
+                const auto &outcome, const auto &fixable) {
+        traces.emplace_back(pointer, name, message, outcome, fixable);
+      },
+      "http://json-schema.org/draft-06/schema#");
+
+  EXPECT_FALSE(result.first);
+  EXPECT_EQ(traces.size(), 1);
+  EXPECT_LINT_TRACE(traces, 0, "", "require_schema_declaration",
+                    "A schema should declare its dialect using the `$schema` "
+                    "keyword",
+                    false);
+}
diff --git a/test/alterschema/alterschema_lint_draft7_test.cc b/test/alterschema/alterschema_lint_draft7_test.cc
index be902c1b0..f9b9f1577 100644
--- a/test/alterschema/alterschema_lint_draft7_test.cc
+++ b/test/alterschema/alterschema_lint_draft7_test.cc
@@ -5352,3 +5352,47 @@ TEST(AlterSchema_lint_draft7,
   EXPECT_EQ(sourcemeta::core::to_string(outcome.locations.at(1)),
             "/patternProperties/[[:digit:]]");
 }
+
+TEST(AlterSchema_lint_draft7, require_schema_declaration_1) {
+  const sourcemeta::core::JSON document = sourcemeta::core::parse_json(R"JSON({
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "title": "My Schema",
+    "description": "A schema",
+    "examples": [ "hello" ],
+    "type": "string"
+  })JSON");
+
+  LINT_WITHOUT_FIX(document, result, traces);
+
+  EXPECT_TRUE(result.first);
+  EXPECT_EQ(traces.size(), 0);
+}
+
+TEST(AlterSchema_lint_draft7, require_schema_declaration_2) {
+  const sourcemeta::core::JSON document = sourcemeta::core::parse_json(R"JSON({
+    "title": "My Schema",
+    "description": "A schema",
+    "examples": [ "hello" ],
+    "type": "string"
+  })JSON");
+
+  std::vector<std::tuple<sourcemeta::core::Pointer, std::string, std::string,
+                         sourcemeta::blaze::SchemaTransformRule::Result, bool>>
+      traces;
+  sourcemeta::blaze::SchemaTransformer bundle;
+  sourcemeta::blaze::add(bundle, sourcemeta::blaze::AlterSchemaMode::Linter);
+  const auto result = bundle.check(
+      document, sourcemeta::blaze::schema_walker, alterschema_test_resolver,
+      [&traces](const auto &pointer, const auto &name, const auto &message,
+                const auto &outcome, const auto &fixable) {
+        traces.emplace_back(pointer, name, message, outcome, fixable);
+      },
+      "http://json-schema.org/draft-07/schema#");
+
+  EXPECT_FALSE(result.first);
+  EXPECT_EQ(traces.size(), 1);
+  EXPECT_LINT_TRACE(traces, 0, "", "require_schema_declaration",
+                    "A schema should declare its dialect using the `$schema` "
+                    "keyword",
+                    false);
+}