diff --git a/package/lib/compileFunctions.js b/package/lib/compileFunctions.js
index d24afbf..22e1d08 100644
--- a/package/lib/compileFunctions.js
+++ b/package/lib/compileFunctions.js
@@ -46,10 +46,13 @@ module.exports = {
         'nodejs8';
       funcTemplate.properties.timeout =
         _.get(funcObject, 'timeout') || _.get(this, 'serverless.service.provider.timeout') || '60s';
-      funcTemplate.properties.environmentVariables = _.merge(
-        {},
-        _.get(this, 'serverless.service.provider.environment'),
-        funcObject.environment // eslint-disable-line comma-dangle
+      funcTemplate.properties.environmentVariables = _.mapValues(
+        _.merge(
+          {},
+          _.get(this, 'serverless.service.provider.environment'),
+          funcObject.environment // eslint-disable-line comma-dangle
+        ),
+        (value) => value.toString() // eslint-disable-line comma-dangle
       );
 
       if (!funcTemplate.properties.serviceAccountEmail) {
diff --git a/package/lib/compileFunctions.test.js b/package/lib/compileFunctions.test.js
index cfdc6f4..6cfbad5 100644
--- a/package/lib/compileFunctions.test.js
+++ b/package/lib/compileFunctions.test.js
@@ -376,6 +376,8 @@ describe('CompileFunctions', () => {
           handler: 'func1',
           environment: {
             TEST_VAR: 'test',
+            TEST_VAR_NUMBER: 123,
+            TEST_VAR_BOOL: false,
           },
           events: [{ http: 'foo' }],
         },
@@ -393,6 +395,8 @@ describe('CompileFunctions', () => {
             availableMemoryMb: 256,
             environmentVariables: {
               TEST_VAR: 'test',
+              TEST_VAR_NUMBER: '123',
+              TEST_VAR_BOOL: 'false',
             },
             timeout: '60s',
             sourceArchiveUrl: 'gs://sls-my-service-dev-12345678/some-path/artifact.zip',