diff --git a/src/index.js b/src/index.js
index 0d148a5..2ef1067 100644
--- a/src/index.js
+++ b/src/index.js
@@ -31,9 +31,13 @@ export default () => {
 
     const queryDocument = gql(source);
 
-    for (const definition of queryDocument.definitions) {
-      if (!definition.name) {
-        throw new Error('GraphQL query must have name.');
+    // If a document contains only one operation, that operation may be unnamed:
+    // https://facebook.github.io/graphql/#sec-Language.Query-Document
+    if (queryDocument.definitions.length > 1) {
+      for (const definition of queryDocument.definitions) {
+        if (!definition.name) {
+          throw new Error('GraphQL query must have name.');
+        }
       }
     }
 
diff --git a/test/fixtures/graphql-tag/transpiles a single unnamed query/actual.js b/test/fixtures/graphql-tag/transpiles a single unnamed query/actual.js
new file mode 100644
index 0000000..c798142
--- /dev/null
+++ b/test/fixtures/graphql-tag/transpiles a single unnamed query/actual.js	
@@ -0,0 +1,3 @@
+import gql from 'graphql-tag';
+
+const foo = gql`{foo}`;
diff --git a/test/fixtures/graphql-tag/transpiles a single unnamed query/expected.js b/test/fixtures/graphql-tag/transpiles a single unnamed query/expected.js
new file mode 100644
index 0000000..f7dd375
--- /dev/null
+++ b/test/fixtures/graphql-tag/transpiles a single unnamed query/expected.js	
@@ -0,0 +1,36 @@
+const foo = {
+  'kind': 'Document',
+  'definitions': [{
+    'kind': 'OperationDefinition',
+    'operation': 'query',
+    'name': null,
+    'variableDefinitions': null,
+    'directives': [],
+    'selectionSet': {
+      'kind': 'SelectionSet',
+      'selections': [{
+        'kind': 'Field',
+        'alias': null,
+        'name': {
+          'kind': 'Name',
+          'value': 'foo'
+        },
+        'arguments': [],
+        'directives': [],
+        'selectionSet': null
+      }]
+    }
+  }],
+  'loc': {
+    'start': 0,
+    'end': 5,
+    'source': {
+      'body': '{foo}',
+      'name': 'GraphQL request',
+      'locationOffset': {
+        'line': 1,
+        'column': 1
+      }
+    }
+  }
+};
diff --git a/test/fixtures/graphql-tag/transpiles a single unnamed query/options.json b/test/fixtures/graphql-tag/transpiles a single unnamed query/options.json
new file mode 100644
index 0000000..5acbd80
--- /dev/null
+++ b/test/fixtures/graphql-tag/transpiles a single unnamed query/options.json	
@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    [
+      "../../../../src"
+    ]
+  ]
+}
diff --git a/test/unnamed-query-test.js b/test/unnamed-query-test.js
new file mode 100644
index 0000000..742ddb5
--- /dev/null
+++ b/test/unnamed-query-test.js
@@ -0,0 +1,29 @@
+import { transform } from 'babel-core';
+import assert from 'assert';
+
+const fixture = "gql`type Widget { name: String } query {widget}`";
+
+describe("When given an unnamed query", () => {
+  let originalError;
+
+  before(function() {
+    originalError = console.error;
+  });
+
+  after(function() {
+    console.error = originalError;
+  });
+
+  it('fails when there are other definitions', () => {
+    const calls = [];
+
+    console.error = (...args) => calls.push(args.join(' '));
+
+    transform(fixture, {
+      plugins: [['./src']]
+    });
+
+    assert.equal(calls.length, 1);
+    assert.equal(calls[0], 'error Error: GraphQL query must have name.');
+  });
+});