@@ -22,6 +22,7 @@
 import java.nio.charset.Charset;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.LinkedHashMap;
 import java.util.LinkedList;
 import java.util.Locale;
 import java.util.Map;
@@ -49,7 +50,9 @@ private Response(Builder builder) {
     this.status = builder.status;
     this.request = builder.request;
     this.reason = builder.reason; // nullable
-    this.headers = Collections.unmodifiableMap(caseInsensitiveCopyOf(builder.headers));
+    this.headers = (builder.headers != null)
+        ? Collections.unmodifiableMap(caseInsensitiveCopyOf(builder.headers))
+        : new LinkedHashMap<>();
     this.body = builder.body; // nullable
   }
 
 
@@ -71,4 +71,14 @@ public void headerValuesWithSameNameOnlyVaryingInCaseAreMerged() {
         Arrays.asList("Cookie-A=Value", "Cookie-B=Value", "Cookie-C=Value");
     assertThat(response.headers()).containsOnly(entry(("set-cookie"), expectedHeaderValue));
   }
+
+  @Test
+  public void headersAreOptional() {
+    Response response = Response.builder()
+        .status(200)
+        .request(Request.create(HttpMethod.GET, "/api", Collections.emptyMap(), null, Util.UTF_8))
+        .body(new byte[0])
+        .build();
+    assertThat(response.headers()).isNotNull().isEmpty();
+  }
 }