diff --git a/src/Generator/RstGeneratorState.ts b/src/Generator/RstGeneratorState.ts
index cb6f760..c57b68b 100644
--- a/src/Generator/RstGeneratorState.ts
+++ b/src/Generator/RstGeneratorState.ts
@@ -314,7 +314,7 @@ export class RstGeneratorState implements SimpleNameResolverProxy {
         const handleNode = () => {
             switch (true) {
                 case node instanceof RstInterpretedText: {
-                    const generator = this._compiler.interpretedTextGenerators.get(node.role)
+                    const generator = this._compiler.interpretedTextGenerators.get(node.role.toLowerCase())
                     if (!generator) {
                         throw new RstGeneratorError(this, node, 'Missing generator')
                     }
@@ -324,7 +324,7 @@ export class RstGeneratorState implements SimpleNameResolverProxy {
                 }
 
                 case node instanceof RstDirective: {
-                    const generator = this._compiler.directiveGenerators.get(node.directive)
+                    const generator = this._compiler.directiveGenerators.get(node.directive.toLowerCase())
                     if (!generator) {
                         throw new RstGeneratorError(this, node, 'Missing generator')
                     }
diff --git a/src/RstCompiler.ts b/src/RstCompiler.ts
index 5019333..d8c426a 100644
--- a/src/RstCompiler.ts
+++ b/src/RstCompiler.ts
@@ -39,13 +39,13 @@ export class RstCompiler {
 
     useDirectiveGenerator(generator: RstDirectiveGenerator) {
         for (const directive of generator.directives) {
-            this.directiveGenerators.set(directive, generator)
+            this.directiveGenerators.set(directive.toLowerCase(), generator)
         }
     }
 
     useInterpretedTextGenerator(generator: RstInterpretedTextGenerator) {
         for (const role of generator.roles) {
-            this.interpretedTextGenerators.set(role, generator)
+            this.interpretedTextGenerators.set(role.toLowerCase(), generator)
         }
     }