diff --git a/CHANGELOG.md b/CHANGELOG.md
index 780886ea..a27f6760 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,7 +1,9 @@
 ## Unreleased
 * support `components.pathItems` so `$ref`s into it resolve, unblocking OpenAPI 3.1 documents that use reusable path items
 * support array-form `type` (3.1) in value validation
+* support root-level `jsonSchemaDialect` (OpenAPI 3.1) in the parse layer
 * add `SpecValidator` with `strict_specification_version` config (`:silent` / `:warn` / `:raise`) to detect version mismatches between declared OpenAPI version and actual field usage
+  * `JsonSchemaDialectIn30`: detect root-level `jsonSchemaDialect` usage in 3.0 documents (3.1 addition)
   * `TypeArrayIn30`: detect array-form `type` usage in 3.0 documents (3.1 form)
   * `NullableDeprecation`: detect `nullable` usage in 3.1 documents (removed in 3.1)
   * `ExampleSingularDeprecation`: detect singular `example` on schemas in 3.1 documents (deprecated in 3.1)
diff --git a/lib/openapi_parser/schemas/openapi.rb b/lib/openapi_parser/schemas/openapi.rb
index 4fa2b747..f80cc367 100644
--- a/lib/openapi_parser/schemas/openapi.rb
+++ b/lib/openapi_parser/schemas/openapi.rb
@@ -50,6 +50,10 @@ def openapi_version
     #   @return [Hash{String => PathItem}, nil] webhook path items (OpenAPI 3.1+)
     openapi_attr_hash_object :webhooks, PathItem, reference: true
 
+    # @!attribute [r] json_schema_dialect
+    #   @return [String, nil] dialect URI for embedded JSON Schemas (OpenAPI 3.1+)
+    openapi_attr_value :json_schema_dialect, schema_key: :jsonSchemaDialect
+
     # @return [OpenAPIParser::RequestOperation, nil]
     def request_operation(http_method, request_path)
       OpenAPIParser::RequestOperation.create(http_method, request_path, @path_item_finder, @config)
diff --git a/lib/openapi_parser/spec_validator.rb b/lib/openapi_parser/spec_validator.rb
index 6c5c4fb6..cb88c59a 100644
--- a/lib/openapi_parser/spec_validator.rb
+++ b/lib/openapi_parser/spec_validator.rb
@@ -2,6 +2,7 @@
 require_relative 'spec_validator/rule'
 require_relative 'spec_validator/rules/exclusive_minimum'
 require_relative 'spec_validator/rules/exclusive_maximum'
+require_relative 'spec_validator/rules/json_schema_dialect_in_30'
 require_relative 'spec_validator/rules/type_array_in_30'
 require_relative 'spec_validator/rules/path_items_in_30'
 require_relative 'spec_validator/rules/nullable_deprecation'
@@ -57,6 +58,7 @@ def rules
         [
           Rules::ExclusiveMinimum,
           Rules::ExclusiveMaximum,
+          Rules::JsonSchemaDialectIn30,
           Rules::TypeArrayIn30,
           Rules::PathItemsIn30,
           Rules::NullableDeprecation,
diff --git a/lib/openapi_parser/spec_validator/rules/json_schema_dialect_in_30.rb b/lib/openapi_parser/spec_validator/rules/json_schema_dialect_in_30.rb
new file mode 100644
index 00000000..c33c3c26
--- /dev/null
+++ b/lib/openapi_parser/spec_validator/rules/json_schema_dialect_in_30.rb
@@ -0,0 +1,19 @@
+module OpenAPIParser
+  class SpecValidator
+    module Rules
+      # `jsonSchemaDialect` is a 3.1 root-level addition; 3.0 has no
+      # equivalent.
+      class JsonSchemaDialectIn30 < Rule
+        def check(root)
+          return [] unless version == :v3_0
+          return [] unless root.raw_schema.is_a?(Hash) && root.raw_schema.key?('jsonSchemaDialect')
+
+          [violation(
+            path: '#/jsonSchemaDialect',
+            message: '`jsonSchemaDialect` is a 3.1 root-level addition; 3.0 documents have no such field',
+          )]
+        end
+      end
+    end
+  end
+end
diff --git a/sig/openapi_parser/spec_validator.rbs b/sig/openapi_parser/spec_validator.rbs
index 3eec7d64..10876456 100644
--- a/sig/openapi_parser/spec_validator.rbs
+++ b/sig/openapi_parser/spec_validator.rbs
@@ -45,6 +45,10 @@ module OpenAPIParser
         def check: (OpenAPIParser::Schemas::OpenAPI root) -> Array[SpecValidator::SpecViolation]
       end
 
+      class JsonSchemaDialectIn30 < Rule
+        def check: (OpenAPIParser::Schemas::OpenAPI root) -> Array[SpecValidator::SpecViolation]
+      end
+
       class TypeArrayIn30 < Rule
         def check: (OpenAPIParser::Schemas::OpenAPI root) -> Array[SpecValidator::SpecViolation]
       end
diff --git a/spec/data/openapi_3_1/json_schema_dialect_30.yaml b/spec/data/openapi_3_1/json_schema_dialect_30.yaml
new file mode 100644
index 00000000..29fcbdb8
--- /dev/null
+++ b/spec/data/openapi_3_1/json_schema_dialect_30.yaml
@@ -0,0 +1,14 @@
+openapi: 3.0.3
+# `jsonSchemaDialect` is a 3.1 root-level addition; 3.0 documents have no
+# such field, so its presence is a spec violation.
+jsonSchemaDialect: https://spec.openapis.org/oas/3.1/dialect/base
+info:
+  title: Inventory API
+  version: '1.0'
+paths:
+  /items:
+    get:
+      summary: List items
+      responses:
+        '200':
+          description: OK
diff --git a/spec/data/openapi_3_1/json_schema_dialect_31.yaml b/spec/data/openapi_3_1/json_schema_dialect_31.yaml
new file mode 100644
index 00000000..ed367c56
--- /dev/null
+++ b/spec/data/openapi_3_1/json_schema_dialect_31.yaml
@@ -0,0 +1,14 @@
+openapi: 3.1.0
+# `jsonSchemaDialect` is a legitimate root-level field in 3.1, so no
+# violation is expected here.
+jsonSchemaDialect: https://spec.openapis.org/oas/3.1/dialect/base
+info:
+  title: Inventory API
+  version: '1.0'
+paths:
+  /items:
+    get:
+      summary: List items
+      responses:
+        '200':
+          description: OK
diff --git a/spec/openapi_parser/spec_validator/integration_3_1_spec.rb b/spec/openapi_parser/spec_validator/integration_3_1_spec.rb
index 001520fa..a49f89b2 100644
--- a/spec/openapi_parser/spec_validator/integration_3_1_spec.rb
+++ b/spec/openapi_parser/spec_validator/integration_3_1_spec.rb
@@ -74,6 +74,20 @@ def expect_clean(file)
     end
   end
 
+  describe 'jsonSchemaDialect (3.1 root-level addition)' do
+    it 'warns on the version-mismatched document under :warn' do
+      expect_mismatch_warns('json_schema_dialect_30.yaml', [:json_schema_dialect_in30])
+    end
+
+    it 'raises SpecViolationError on the version-mismatched document under :raise' do
+      expect_mismatch_raises('json_schema_dialect_30.yaml', [:json_schema_dialect_in30])
+    end
+
+    it 'stays clean on the correctly-versioned document' do
+      expect_clean('json_schema_dialect_31.yaml')
+    end
+  end
+
   describe 'type as an Array of names (3.1 form rejected by 3.0)' do
     it 'warns on the version-mismatched document under :warn' do
       expect_mismatch_warns('type_array_30.yaml', [:type_array_in30])
diff --git a/spec/openapi_parser/spec_validator/rules/json_schema_dialect_in_30_spec.rb b/spec/openapi_parser/spec_validator/rules/json_schema_dialect_in_30_spec.rb
new file mode 100644
index 00000000..47396317
--- /dev/null
+++ b/spec/openapi_parser/spec_validator/rules/json_schema_dialect_in_30_spec.rb
@@ -0,0 +1,79 @@
+require_relative '../../../spec_helper'
+
+RSpec.describe 'OpenAPIParser::SpecValidator::Rules::JsonSchemaDialectIn30' do
+  def base_doc(openapi_version_string)
+    {
+      'openapi' => openapi_version_string,
+      'info' => { 'title' => 'test', 'version' => '1.0' },
+      'paths' => {},
+    }
+  end
+
+  def doc_with_dialect(openapi_version_string)
+    raw = base_doc(openapi_version_string)
+    raw['jsonSchemaDialect'] = 'https://spec.openapis.org/oas/3.1/dialect/base'
+    OpenAPIParser.parse(raw, strict_reference_validation: false)
+  end
+
+  def doc_without_dialect(openapi_version_string)
+    OpenAPIParser.parse(base_doc(openapi_version_string), strict_reference_validation: false)
+  end
+
+  def run_rule_for(root)
+    OpenAPIParser::SpecValidator::Rules::JsonSchemaDialectIn30.new(root.openapi_version).check(root)
+  end
+
+  context 'with a 3.1 document declaring jsonSchemaDialect' do
+    it 'reports no violation' do
+      root = doc_with_dialect('3.1.0')
+      expect(run_rule_for(root)).to eq []
+    end
+  end
+
+  context 'with a 3.1 document without jsonSchemaDialect' do
+    it 'reports no violation' do
+      root = doc_without_dialect('3.1.0')
+      expect(run_rule_for(root)).to eq []
+    end
+  end
+
+  context 'with a 3.0 document declaring jsonSchemaDialect' do
+    it 'reports one violation pointing at #/jsonSchemaDialect' do
+      root = doc_with_dialect('3.0.0')
+      violations = run_rule_for(root)
+      expect(violations.size).to eq 1
+      expect(violations.first.path).to eq '#/jsonSchemaDialect'
+      expect(violations.first.rule_name).to eq :json_schema_dialect_in30
+    end
+  end
+
+  context 'with a 3.0 document without jsonSchemaDialect' do
+    it 'reports no violation' do
+      root = doc_without_dialect('3.0.0')
+      expect(run_rule_for(root)).to eq []
+    end
+  end
+
+  context 'with an :unknown version document' do
+    it 'reports no violation (rule skipped)' do
+      root = doc_with_dialect('4.0.0')
+      expect(run_rule_for(root)).to eq []
+    end
+  end
+end
+
+RSpec.describe 'OpenAPI#json_schema_dialect parse layer' do
+  let(:root) do
+    raw = {
+      'openapi' => '3.1.0',
+      'info' => { 'title' => 'test', 'version' => '1.0' },
+      'paths' => {},
+      'jsonSchemaDialect' => 'https://spec.openapis.org/oas/3.1/dialect/base',
+    }
+    OpenAPIParser.parse(raw, strict_reference_validation: false)
+  end
+
+  it 'exposes the dialect URI string' do
+    expect(root.json_schema_dialect).to eq 'https://spec.openapis.org/oas/3.1/dialect/base'
+  end
+end