diff --git a/language-server/src/server.js b/language-server/src/server.js
index 4950c4e..e81c279 100644
--- a/language-server/src/server.js
+++ b/language-server/src/server.js
@@ -5,6 +5,7 @@ import {
   DiagnosticTag,
   DidChangeWatchedFilesNotification,
   ProposedFeatures,
+  DidChangeConfigurationNotification,
   SemanticTokensBuilder,
   TextDocuments,
   TextDocumentSyncKind
@@ -38,9 +39,13 @@ connection.console.log("Starting JSON Schema service ...");
 
 let hasWorkspaceFolderCapability = false;
 let hasWorkspaceWatchCapability = false;
+let hasConfigurationCapability = false;
 
 connection.onInitialize(({ capabilities, workspaceFolders }) => {
   connection.console.log("Initializing JSON Schema service ...");
+  hasConfigurationCapability = !!(
+    capabilities.workspace && !!capabilities.workspace.configuration
+  );
 
   if (workspaceFolders) {
     addWorkspaceFolders(workspaceFolders);
@@ -73,6 +78,10 @@ connection.onInitialize(({ capabilities, workspaceFolders }) => {
 });
 
 connection.onInitialized(async () => {
+  if (hasConfigurationCapability) {
+    connection.client.register(DidChangeConfigurationNotification.type);
+  }
+
   if (hasWorkspaceWatchCapability) {
     connection.client.register(DidChangeWatchedFilesNotification.type, {
       watchers: [
@@ -136,6 +145,37 @@ connection.listen();
 
 const documents = new TextDocuments(TextDocument);
 
+// CONFIGURATION
+
+const documentSettings = new Map();
+let globalSettings = {};
+
+async function getDocumentSettings(resource) {
+  if (!hasConfigurationCapability) {
+    return globalSettings;
+  }
+
+  if (!documentSettings.has(resource)) {
+    const result = await connection.workspace.getConfiguration({
+      scopeUri: resource,
+      section: "jsonSchemaLanguageServer"
+    });
+    documentSettings.set(resource, result ?? globalSettings);
+  }
+
+  return documentSettings.get(resource);
+}
+
+connection.onDidChangeConfiguration((change) => {
+  if (hasConfigurationCapability) {
+    documentSettings.clear();
+  } else {
+    globalSettings = change.settings.jsonSchemaLanguageServer ?? globalSettings;
+  }
+
+  validateWorkspace();
+});
+
 // INLINE ERRORS
 
 documents.onDidChangeContent(async ({ document }) => {
@@ -150,19 +190,22 @@ documents.onDidChangeContent(async ({ document }) => {
 const validateSchema = async (document) => {
   const diagnostics = [];
 
+  const settings = await getDocumentSettings(document.uri);
   const instance = JsoncInstance.fromTextDocument(document);
   if (instance.typeOf() === "undefined") {
     return;
   }
 
   const $schema = instance.get("#/$schema");
-  const contextDialectUri = $schema.value();
+  const contextDialectUri = $schema.value() ?? settings.defaultDialect;
   const schemaResources = decomposeSchemaDocument(instance, contextDialectUri);
   for (const { dialectUri, schemaInstance } of schemaResources) {
     if (!hasDialect(dialectUri)) {
       const $schema = schemaInstance.get("#/$schema");
       if ($schema.typeOf() === "string") {
         diagnostics.push(buildDiagnostic($schema, "Unknown dialect"));
+      } else if (contextDialectUri) {
+        diagnostics.push(buildDiagnostic(schemaInstance, "Unknown dialect"));
       } else {
         diagnostics.push(buildDiagnostic(schemaInstance, "No dialect"));
       }
@@ -260,9 +303,10 @@ const getTokenBuilder = (uri) => {
   return result;
 };
 
-const buildTokens = (builder, document) => {
+const buildTokens = (builder, document, settings) => {
   const instance = JsoncInstance.fromTextDocument(document);
-  const dialectUri = instance.get("#/$schema").value();
+  const $schema = instance.get("#/$schema");
+  const dialectUri = $schema.value() ?? settings.defaultDialect;
   const schemaResources = decomposeSchemaDocument(instance, dialectUri);
   for (const { keywordInstance, tokenType, tokenModifier } of getSemanticTokens(schemaResources)) {
     const startPosition = keywordInstance.startPosition();
@@ -276,13 +320,14 @@ const buildTokens = (builder, document) => {
   }
 };
 
-connection.languages.semanticTokens.on(({ textDocument }) => {
+connection.languages.semanticTokens.on(async ({ textDocument }) => {
   connection.console.log(`semanticTokens.on: ${textDocument.uri}`);
 
   if (isSchema(textDocument.uri)) {
     const builder = getTokenBuilder(textDocument.uri);
     const document = documents.get(textDocument.uri);
-    buildTokens(builder, document);
+    const settings = await getDocumentSettings(document.uri);
+    buildTokens(builder, document, settings);
 
     return builder.build();
   } else {
@@ -290,17 +335,18 @@ connection.languages.semanticTokens.on(({ textDocument }) => {
   }
 });
 
-connection.languages.semanticTokens.onDelta(({ textDocument, previousResultId }) => {
+connection.languages.semanticTokens.onDelta(async ({ textDocument, previousResultId }) => {
   connection.console.log(`semanticTokens.onDelta: ${textDocument.uri}`);
 
   const document = documents.get(textDocument.uri);
+  const settings = await getDocumentSettings(document.uri);
   if (document === undefined) {
     return { edits: [] };
   }
 
   const builder = getTokenBuilder(document);
   builder.previousResult(previousResultId);
-  buildTokens(builder, document);
+  buildTokens(builder, document, settings);
 
   return builder.buildEdits();
 });
diff --git a/vscode/package.json b/vscode/package.json
index 9994357..491b4ec 100644
--- a/vscode/package.json
+++ b/vscode/package.json
@@ -32,5 +32,14 @@
     "onLanguage:json"
   ],
   "contributes": {
+    "configuration": {
+      "title": "Configuration for JSON Schema Language Server",
+      "properties": {
+        "jsonSchemaLanguageServer.defaultDialect": {
+          "type": "string",
+          "description": "The default JSON Schema dialect to use if none is specified in the schema document"
+        }
+      }
+    }
   }
-}
+}
\ No newline at end of file