diff --git a/gradle-language-server/src/main/java/com/microsoft/gradle/GradleServices.java b/gradle-language-server/src/main/java/com/microsoft/gradle/GradleServices.java
index 0ca17e3a6..df22fb099 100644
--- a/gradle-language-server/src/main/java/com/microsoft/gradle/GradleServices.java
+++ b/gradle-language-server/src/main/java/com/microsoft/gradle/GradleServices.java
@@ -298,15 +298,22 @@ public CompletableFuture<Either<List<CompletionItem>, CompletionList>> completio
 			}
 		}
 		Set<MethodCallExpression> methodCalls = this.completionVisitor.getMethodCalls(uri);
-		MethodCallExpression containingCall = null;
+		List<MethodCallExpression> containingCallPath = new ArrayList<>();
+		MethodCallExpression lastCall = null;
 		for (MethodCallExpression call : methodCalls) {
 			Expression expression = call.getArguments();
 			Range range = LSPUtils.toRange(expression);
-			if (Ranges.containsPosition(range, params.getPosition())
-					&& (containingCall == null || Ranges.containsRange(LSPUtils.toRange(containingCall.getArguments()),
-							LSPUtils.toRange(call.getArguments())))) {
-				// find inner containing call
-				containingCall = call;
+			if (Ranges.containsPosition(range, params.getPosition())) {
+				lastCall = call;
+				if (Ranges.containsRange(LSPUtils.toRange(lastCall.getArguments()),
+						LSPUtils.toRange(call.getArguments()))) {
+					// if current call contains inside last call, nested closure.
+					containingCallPath.add(call);
+				} else if (Ranges.containsRange(LSPUtils.toRange(call.getArguments()),
+						LSPUtils.toRange(lastCall.getArguments()))) {
+					// if current call is the parent of last call, nested closure.
+					containingCallPath.add(containingCallPath.size() - 1, call);
+				}
 			}
 		}
 		this.libraryResolver.loadGradleClasses();
@@ -315,11 +322,11 @@ public CompletableFuture<Either<List<CompletionItem>, CompletionList>> completio
 		CompletionHandler handler = new CompletionHandler();
 		// check again
 		String projectPath = Utils.getFolderPath(uri);
-		if (containingCall == null && isGradleRoot(uri, params.getPosition())) {
-			return CompletableFuture.completedFuture(Either.forLeft(handler.getCompletionItems(null,
+		if (containingCallPath.isEmpty() && isGradleRoot(uri, params.getPosition())) {
+			return CompletableFuture.completedFuture(Either.forLeft(handler.getCompletionItems(Collections.emptyList(),
 					Paths.get(uri).getFileName().toString(), this.libraryResolver, javaPluginsIncluded, projectPath)));
 		}
-		return CompletableFuture.completedFuture(Either.forLeft(handler.getCompletionItems(containingCall,
+		return CompletableFuture.completedFuture(Either.forLeft(handler.getCompletionItems(containingCallPath,
 				Paths.get(uri).getFileName().toString(), this.libraryResolver, javaPluginsIncluded, projectPath)));
 	}
 
diff --git a/gradle-language-server/src/main/java/com/microsoft/gradle/handlers/CompletionHandler.java b/gradle-language-server/src/main/java/com/microsoft/gradle/handlers/CompletionHandler.java
index 438f29318..f5424016c 100644
--- a/gradle-language-server/src/main/java/com/microsoft/gradle/handlers/CompletionHandler.java
+++ b/gradle-language-server/src/main/java/com/microsoft/gradle/handlers/CompletionHandler.java
@@ -17,6 +17,7 @@
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
+import java.util.stream.Collectors;
 import org.apache.bcel.classfile.Attribute;
 import org.apache.bcel.classfile.FieldOrMethod;
 import org.apache.bcel.classfile.JavaClass;
@@ -35,12 +36,12 @@ public class CompletionHandler {
 	private static String SETTING_GRADLE = "settings.gradle";
 	private static String DEPENDENCYHANDLER_CLASS = "org.gradle.api.artifacts.dsl.DependencyHandler";
 
-	public List<CompletionItem> getCompletionItems(MethodCallExpression containingCall, String fileName,
+	public List<CompletionItem> getCompletionItems(List<MethodCallExpression> containingCallPath, String fileName,
 			GradleLibraryResolver resolver, boolean javaPluginsIncluded, String projectPath) {
 		List<CompletionItem> results = new ArrayList<>();
 		Set<String> resultSet = new HashSet<>();
 		List<String> delegateClassNames = new ArrayList<>();
-		if (containingCall == null) {
+		if (containingCallPath.isEmpty()) {
 			if (fileName.equals(BUILD_GRADLE)) {
 				delegateClassNames.add(GradleDelegate.getDefault());
 			} else if (fileName.equals(SETTING_GRADLE)) {
@@ -48,7 +49,8 @@ public List<CompletionItem> getCompletionItems(MethodCallExpression containingCa
 			}
 			results.addAll(getCompletionItemsFromExtClosures(resolver, projectPath, resultSet));
 		} else {
-			String methodName = containingCall.getMethodAsString();
+			String methodName = containingCallPath.stream().map(MethodCallExpression::getMethodAsString)
+					.collect(Collectors.joining("."));
 			List<CompletionItem> re = getCompletionItemsFromExtClosures(resolver, projectPath, methodName, resultSet);
 			results.addAll(re);
 			List<String> delegates = GradleDelegate.getDelegateMap().get(methodName);
diff --git a/gradle-plugin/src/main/java/com/microsoft/gradle/GradleProjectModelBuilder.java b/gradle-plugin/src/main/java/com/microsoft/gradle/GradleProjectModelBuilder.java
index 960f42e84..9cfade6c2 100644
--- a/gradle-plugin/src/main/java/com/microsoft/gradle/GradleProjectModelBuilder.java
+++ b/gradle-plugin/src/main/java/com/microsoft/gradle/GradleProjectModelBuilder.java
@@ -15,6 +15,8 @@
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashSet;
@@ -192,31 +194,60 @@ private List<GradleClosure> getPluginClosures(Project project) {
 		for (ExtensionSchema schema : extensionsSchema.getElements()) {
 			TypeOf<?> publicType = schema.getPublicType();
 			Class<?> concreteClass = publicType.getConcreteClass();
-			List<GradleMethod> methods = new ArrayList<>();
-			List<GradleField> fields = new ArrayList<>();
-			for (Method method : concreteClass.getMethods()) {
-				String name = method.getName();
-				List<String> parameterTypes = new ArrayList<>();
-				for (Class<?> parameterType : method.getParameterTypes()) {
-					parameterTypes.add(parameterType.getName());
-				}
-				methods.add(new DefaultGradleMethod(name, parameterTypes, isDeprecated(method)));
-				int modifiers = method.getModifiers();
-				// See:
-				// https://docs.gradle.org/current/userguide/custom_gradle_types.html#managed_properties
-				// we offer managed properties for an abstract getter method
-				if (name.startsWith("get") && name.length() > 3 && Modifier.isPublic(modifiers)
-						&& Modifier.isAbstract(modifiers)) {
-					fields.add(new DefaultGradleField(name.substring(3, 4).toLowerCase() + name.substring(4),
-							isDeprecated(method)));
+			closures.addAll(buildClosure(schema.getName(), concreteClass));
+		}
+		return closures;
+	}
+
+	/**
+	 * @param closureName
+	 * @param concreteClass
+	 * @return
+	 */
+	private List<DefaultGradleClosure> buildClosure(String closureName, Class<?> concreteClass) {
+		List<DefaultGradleClosure> closures = new ArrayList<>();
+		List<GradleMethod> methods = new ArrayList<>();
+		List<GradleField> fields = new ArrayList<>();
+		for (Method method : concreteClass.getMethods()) {
+			String name = method.getName();
+			List<String> parameterTypes = new ArrayList<>();
+			for (Class<?> parameterType : method.getParameterTypes()) {
+				parameterTypes.add(parameterType.getName());
+			}
+
+			// check for nested closure methods and include them in the final closure list
+			// for completions.
+			if (method.getGenericParameterTypes().length == 1) {
+				Type parameterType = method.getGenericParameterTypes()[0];
+				if (parameterType.getTypeName().startsWith("org.gradle.api.Action<")
+						&& (parameterType instanceof ParameterizedType)) {
+					Type[] actualTypeArguments = ((ParameterizedType) parameterType).getActualTypeArguments();
+					if (actualTypeArguments.length == 1) {
+						try {
+							closures.addAll(buildClosure(closureName.concat(".").concat(name),
+									concreteClass.getClassLoader().loadClass(actualTypeArguments[0].getTypeName())));
+						} catch (ClassNotFoundException e) {
+							// continue if we cannot find the extension class.
+						}
+					}
 				}
 			}
-			for (Field field : concreteClass.getFields()) {
-				fields.add(new DefaultGradleField(field.getName(), isDeprecated(field)));
+
+			methods.add(new DefaultGradleMethod(name, parameterTypes, isDeprecated(method)));
+			int modifiers = method.getModifiers();
+			// See:
+			// https://docs.gradle.org/current/userguide/custom_gradle_types.html#managed_properties
+			// we offer managed properties for an abstract getter method
+			if (name.startsWith("get") && name.length() > 3 && Modifier.isPublic(modifiers)
+					&& Modifier.isAbstract(modifiers)) {
+				fields.add(new DefaultGradleField(name.substring(3, 4).toLowerCase() + name.substring(4),
+						isDeprecated(method)));
 			}
-			DefaultGradleClosure closure = new DefaultGradleClosure(schema.getName(), methods, fields);
-			closures.add(closure);
 		}
+		for (Field field : concreteClass.getFields()) {
+			fields.add(new DefaultGradleField(field.getName(), isDeprecated(field)));
+		}
+		closures.add(new DefaultGradleClosure(closureName, methods, fields));
 		return closures;
 	}