diff --git a/pom.xml b/pom.xml
index e71473b183..e64f858714 100644
--- a/pom.xml
+++ b/pom.xml
@@ -51,7 +51,7 @@
     <android.platform>16</android.platform>
     <gson.version>2.2.4</gson.version>
     <okhttp.version>1.3.0</okhttp.version>
-    <rxjava.version>0.17.1</rxjava.version>
+    <rxjava.version>0.18.1</rxjava.version>
     <appengine.version>1.8.9</appengine.version>
 
     <!-- Converter Dependencies -->
diff --git a/retrofit-mock/src/main/java/retrofit/MockRestAdapter.java b/retrofit-mock/src/main/java/retrofit/MockRestAdapter.java
index 7b1c1ff91e..1746c13d98 100644
--- a/retrofit-mock/src/main/java/retrofit/MockRestAdapter.java
+++ b/retrofit-mock/src/main/java/retrofit/MockRestAdapter.java
@@ -8,13 +8,12 @@
 import java.lang.reflect.Proxy;
 import java.util.Map;
 import java.util.Random;
+import java.util.concurrent.Executor;
 import java.util.concurrent.TimeUnit;
 import retrofit.client.Request;
 import retrofit.client.Response;
 import rx.Observable;
-import rx.Scheduler;
 import rx.Subscriber;
-import rx.schedulers.Schedulers;
 
 import static retrofit.RestAdapter.LogLevel;
 import static retrofit.RetrofitError.unexpectedError;
@@ -525,30 +524,36 @@ private static long uptimeMillis() {
 
   /** Indirection to avoid VerifyError if RxJava isn't present. */
   private static class MockRxSupport {
-    private final Scheduler scheduler;
+    private final Executor httpExecutor;
     private final ErrorHandler errorHandler;
 
     MockRxSupport(RestAdapter restAdapter) {
-      scheduler = Schedulers.executor(restAdapter.httpExecutor);
+      httpExecutor = restAdapter.httpExecutor;
       errorHandler = restAdapter.errorHandler;
     }
 
     Observable createMockObservable(final MockHandler mockHandler, final RestMethodInfo methodInfo,
         final RequestInterceptor interceptor, final Object[] args) {
       return Observable.create(new Observable.OnSubscribe<Object>() {
-        @Override public void call(Subscriber<? super Object> subscriber) {
-          try {
-            Observable observable =
-                (Observable) mockHandler.invokeSync(methodInfo, interceptor, args);
-            //noinspection unchecked
-            observable.subscribe(subscriber);
-          } catch (RetrofitError e) {
-            subscriber.onError(errorHandler.handleError(e));
-          } catch (Throwable e) {
-            subscriber.onError(e);
-          }
+        @Override public void call(final Subscriber<? super Object> subscriber) {
+          if (subscriber.isUnsubscribed()) return;
+          httpExecutor.execute(new Runnable() {
+            @Override public void run() {
+              try {
+                if (subscriber.isUnsubscribed()) return;
+                Observable observable =
+                        (Observable) mockHandler.invokeSync(methodInfo, interceptor, args);
+                //noinspection unchecked
+                observable.subscribe(subscriber);
+              } catch (RetrofitError e) {
+                subscriber.onError(errorHandler.handleError(e));
+              } catch (Throwable e) {
+                subscriber.onError(e);
+              }
+            }
+          });
         }
-      }).subscribeOn(scheduler);
+      });
     }
   }
 }
diff --git a/retrofit/src/main/java/retrofit/RestAdapter.java b/retrofit/src/main/java/retrofit/RestAdapter.java
index 18174734fd..ba2941f3d4 100644
--- a/retrofit/src/main/java/retrofit/RestAdapter.java
+++ b/retrofit/src/main/java/retrofit/RestAdapter.java
@@ -27,6 +27,7 @@
 import java.util.concurrent.Callable;
 import java.util.concurrent.Executor;
 import java.util.concurrent.TimeUnit;
+
 import retrofit.Profiler.RequestInformation;
 import retrofit.client.Client;
 import retrofit.client.Header;
@@ -38,10 +39,6 @@
 import retrofit.mime.TypedByteArray;
 import retrofit.mime.TypedInput;
 import retrofit.mime.TypedOutput;
-import rx.Observable;
-import rx.Scheduler;
-import rx.Subscriber;
-import rx.schedulers.Schedulers;
 
 /**
  * Adapts a Java interface to a REST API.
@@ -227,40 +224,6 @@ static RestMethodInfo getMethodInfo(Map<Method, RestMethodInfo> cache, Method me
     }
   }
 
-  /** Indirection to avoid VerifyError if RxJava isn't present. */
-  private static final class RxSupport {
-    private final Scheduler scheduler;
-    private final ErrorHandler errorHandler;
-
-    RxSupport(Executor executor, ErrorHandler errorHandler) {
-      this.scheduler = Schedulers.executor(executor);
-      this.errorHandler = errorHandler;
-    }
-
-    Observable createRequestObservable(final Callable<ResponseWrapper> request) {
-      return Observable.create(new Observable.OnSubscribe<Object>() {
-        @Override public void call(Subscriber<? super Object> subscriber) {
-          if (subscriber.isUnsubscribed()) {
-            return;
-          }
-          try {
-            ResponseWrapper wrapper = request.call();
-            if (subscriber.isUnsubscribed()) {
-              return;
-            }
-            subscriber.onNext(wrapper.responseBody);
-            subscriber.onCompleted();
-          } catch (RetrofitError e) {
-            subscriber.onError(errorHandler.handleError(e));
-          } catch (Exception e) {
-            // This is from the Callable.  It shouldn't actually throw.
-            throw new RuntimeException(e);
-          }
-        }
-      }).subscribeOn(scheduler);
-    }
-  }
-
   private class RestHandler implements InvocationHandler {
     private final Map<Method, RestMethodInfo> methodDetailsCache;
 
diff --git a/retrofit/src/main/java/retrofit/RxSupport.java b/retrofit/src/main/java/retrofit/RxSupport.java
new file mode 100644
index 0000000000..b728205e72
--- /dev/null
+++ b/retrofit/src/main/java/retrofit/RxSupport.java
@@ -0,0 +1,65 @@
+package retrofit;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.Executor;
+import java.util.concurrent.FutureTask;
+
+import rx.Observable;
+import rx.Subscriber;
+import rx.Subscription;
+import rx.subscriptions.Subscriptions;
+
+/**
+ * Utilities for supporting RxJava Observables.
+ * Used primarily by {@link retrofit.RestAdapter}.
+ *
+ * Remember RxJava might not be on the classpath, check its included before calling, use
+ * {@link Platform#HAS_RX_JAVA}
+ */
+final class RxSupport {
+  private final Executor executor;
+  private final ErrorHandler errorHandler;
+
+  RxSupport(Executor executor, ErrorHandler errorHandler) {
+    this.executor = executor;
+    this.errorHandler = errorHandler;
+  }
+
+  Observable createRequestObservable(final Callable<ResponseWrapper> request) {
+    return Observable.create(new Observable.OnSubscribe<Object>() {
+      @Override public void call(Subscriber<? super Object> subscriber) {
+        if (subscriber.isUnsubscribed()) {
+          return;
+        }
+        final FutureTask<Void> task = new FutureTask<Void>(getRunnable(subscriber, request), null);
+        final Subscription s = Subscriptions.from(task);
+        // We add our subscription to the current subscriber so the future task can be
+        // unSubscribed from.
+        subscriber.add(s);
+        executor.execute(task);
+      }
+    });
+  }
+
+  private Runnable getRunnable(final Subscriber<? super Object> subscriber,
+                               final Callable<ResponseWrapper> request) {
+    return new Runnable() {
+      @Override public void run() {
+        try {
+          if (subscriber.isUnsubscribed()) {
+            return;
+          }
+          ResponseWrapper wrapper = request.call();
+          subscriber.onNext(wrapper.responseBody);
+          subscriber.onCompleted();
+        } catch (RetrofitError e) {
+          subscriber.onError(errorHandler.handleError(e));
+        } catch (Exception e) {
+          // This is from the Callable.  It shouldn't actually throw.
+          throw new RuntimeException(e);
+        }
+      }
+    };
+  }
+
+}
diff --git a/retrofit/src/test/java/retrofit/RxSupportTest.java b/retrofit/src/test/java/retrofit/RxSupportTest.java
new file mode 100644
index 0000000000..e37da9c513
--- /dev/null
+++ b/retrofit/src/test/java/retrofit/RxSupportTest.java
@@ -0,0 +1,186 @@
+package retrofit;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.util.ArrayDeque;
+import java.util.Collections;
+import java.util.Deque;
+import java.util.Iterator;
+import java.util.concurrent.Callable;
+import java.util.concurrent.Executor;
+import java.util.concurrent.TimeUnit;
+
+import retrofit.client.Header;
+import retrofit.client.Response;
+import retrofit.mime.TypedInput;
+import rx.Observer;
+import rx.Subscription;
+import rx.schedulers.Schedulers;
+import rx.schedulers.TestScheduler;
+
+import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+public class RxSupportTest {
+
+  private Object response;
+  private ResponseWrapper responseWrapper;
+  private Callable<ResponseWrapper> callable = spy(new Callable<ResponseWrapper>() {
+    @Override public ResponseWrapper call() throws Exception {
+      return responseWrapper;
+    }
+  });
+
+  private QueuedSynchronousExecutor executor;
+  private ErrorHandler errorHandler;
+  private RxSupport rxSupport;
+
+  @Before
+  public void setUp() throws Exception {
+    MockitoAnnotations.initMocks(this);
+    response = new Object();
+    responseWrapper = new ResponseWrapper(
+            new Response(
+                    "http://example.com", 200, "Success",
+                    Collections.<Header>emptyList(), mock(TypedInput.class)
+            ), response
+    );
+    executor = spy(new QueuedSynchronousExecutor());
+    errorHandler = ErrorHandler.DEFAULT;
+    rxSupport = new RxSupport(executor, errorHandler);
+  }
+
+  @Mock
+  Observer<Object> subscriber;
+
+  @Test
+  public void testObservableCallsOnNextOnHttpExecutor() throws Exception {
+    rxSupport.createRequestObservable(callable).subscribe(subscriber);
+    executor.executeNextInQueue();
+    verify(subscriber, times(1)).onNext(response);
+  }
+
+  @Test
+  public void testObservableCallsOnNextOnHttpExecutorWithSubscriber() throws Exception {
+    TestScheduler test = Schedulers.test();
+    rxSupport.createRequestObservable(callable).subscribeOn(test).subscribe(subscriber);
+    // Subscription is handled via the Scheduler.
+    test.triggerActions();
+    // This will only execute up to the executor in OnSubscribe.
+    verify(subscriber, never()).onNext(any());
+    // Upon continuing the executor we then run the retrofit request.
+    executor.executeNextInQueue();
+    verify(subscriber, times(1)).onNext(response);
+  }
+
+  @Test
+  public void testObservableUnSubscribesDoesNotExecuteCallable() throws Exception {
+    Subscription subscription = rxSupport.createRequestObservable(callable).subscribe(subscriber);
+    verify(subscriber, never()).onNext(any());
+
+    // UnSubscribe here should cancel the queued runnable.
+    subscription.unsubscribe();
+
+    executor.executeNextInQueue();
+    verify(callable, never()).call();
+    verify(subscriber, never()).onNext(response);
+  }
+
+  @Test
+  public void testObservableCallsOperatorsOffHttpExecutor() throws Exception {
+    TestScheduler test = Schedulers.test();
+    rxSupport.createRequestObservable(callable)
+            .delaySubscription(1000, TimeUnit.MILLISECONDS, test)
+            .subscribe(subscriber);
+
+    verify(subscriber, never()).onNext(any());
+    test.advanceTimeBy(1000, TimeUnit.MILLISECONDS);
+    // Upon continuing the executor we then run the retrofit request.
+    executor.executeNextInQueue();
+    verify(subscriber, times(1)).onNext(response);
+  }
+
+  @Test
+  public void testObservableDoesNotLockExecutor() throws Exception {
+    TestScheduler test = Schedulers.test();
+    Subscription subscription1 = rxSupport.createRequestObservable(callable)
+            .delay(1000, TimeUnit.MILLISECONDS, test)
+            .subscribe(subscriber);
+
+    Subscription subscription2 = rxSupport.createRequestObservable(callable)
+            .delay(2000, TimeUnit.MILLISECONDS, test)
+            .subscribe(subscriber);
+
+    // Nothing fired yet
+    verify(subscriber, never()).onNext(any());
+    // Subscriptions should of been queued up and executed even tho we delayed on the Subscriber.
+    executor.executeNextInQueue();
+    executor.executeNextInQueue();
+
+    verify(subscriber, never()).onNext(response);
+
+    test.advanceTimeBy(1000, TimeUnit.MILLISECONDS);
+    verify(subscriber, times(1)).onNext(response);
+
+    test.advanceTimeBy(1000, TimeUnit.MILLISECONDS);
+    verify(subscriber, times(2)).onNext(response);
+  }
+
+  @Test
+  public void testObservableRespectsObserveOn() throws Exception {
+    TestScheduler observe = Schedulers.test();
+    rxSupport.createRequestObservable(callable)
+            .observeOn(observe)
+            .subscribe(subscriber);
+
+    verify(subscriber, never()).onNext(any());
+    executor.executeNextInQueue();
+
+    // Should have no response yet, but callback should of been executed.
+    verify(subscriber, never()).onNext(any());
+    verify(callable, times(1)).call();
+
+    // Forward the Observable Scheduler
+    observe.triggerActions();
+    verify(subscriber, times(1)).onNext(response);
+  }
+
+  /**
+   * Test Executor to iterate through Executions to aid in checking
+   * that the Observable implementation is correct.
+   */
+  static class QueuedSynchronousExecutor implements Executor {
+    Deque<Runnable> runnableQueue = new ArrayDeque<Runnable>();
+
+    @Override public void execute(Runnable runnable) {
+      runnableQueue.add(runnable);
+    }
+
+    /**
+     * Will throw exception if you are expecting something to be added to the Executor
+     * and it hasn't.
+     */
+    void executeNextInQueue() {
+      runnableQueue.removeFirst().run();
+    }
+
+    /**
+     * Executes any queued executions on the executor.
+     */
+    void executeAll() {
+      Iterator<Runnable> iterator = runnableQueue.iterator();
+      while (iterator.hasNext()) {
+        Runnable next = iterator.next();
+        next.run();
+        iterator.remove();
+      }
+    }
+  }
+}
\ No newline at end of file