diff --git a/package/lib/compileFunctions.js b/package/lib/compileFunctions.js
index b318d47..55e43d9 100644
--- a/package/lib/compileFunctions.js
+++ b/package/lib/compileFunctions.js
@@ -47,10 +47,9 @@ 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),
+        (value, key, result) => coerceEnvOrError(result, key, value)
       );
       funcTemplate.accessControl.gcpIamPolicy.bindings = _.unionBy(
         _.get(funcObject, 'iam.bindings'),
@@ -198,6 +197,19 @@ const validateIamProperty = (funcObject, functionName) => {
   }
 };
 
+const coerceEnvOrError = (result, key, value) => {
+  if (typeof value === 'string') {
+    return value;
+  } else if (typeof value === 'number') {
+    return value.toString();
+  }
+  const errorMessage = [
+    `The value for environment variable ${key} is an unsupported type: ${typeof value}.`,
+    ' Values must either be strings or numbers (which are coerced into strings at package time).',
+  ].join('');
+  throw new Error(errorMessage);
+};
+
 const getFunctionTemplate = (funcObject, projectName, region, sourceArchiveUrl) => {
   //eslint-disable-line
   return {
diff --git a/package/lib/compileFunctions.test.js b/package/lib/compileFunctions.test.js
index a4c764d..78cb02b 100644
--- a/package/lib/compileFunctions.test.js
+++ b/package/lib/compileFunctions.test.js
@@ -370,12 +370,72 @@ describe('CompileFunctions', () => {
       });
     });
 
+    it('should fail setting environment variable due to unsupported type (bool)', () => {
+      googlePackage.serverless.service.functions = {
+        func1: {
+          handler: 'func1',
+          environment: {
+            TEST_VAR: true,
+          },
+          events: [{ http: 'foo' }],
+        },
+      };
+
+      expect(() => googlePackage.compileFunctions()).toThrow(Error);
+    });
+
+    it('should fail setting environment variable due to unsupported type (null)', () => {
+      googlePackage.serverless.service.functions = {
+        func1: {
+          handler: 'func1',
+          environment: {
+            TEST_VAR: null,
+          },
+          events: [{ http: 'foo' }],
+        },
+      };
+
+      expect(() => googlePackage.compileFunctions()).toThrow(Error);
+    });
+
+    it('should fail setting environment variable due to unsupported type (object)', () => {
+      googlePackage.serverless.service.functions = {
+        func1: {
+          handler: 'func1',
+          environment: {
+            dev: {
+              TEST_VAR: 'test',
+            },
+          },
+          events: [{ http: 'foo' }],
+        },
+      };
+
+      expect(() => googlePackage.compileFunctions()).toThrow(Error);
+    });
+
+    it('should fail setting environment variable from provider due to unsupported type (bool)', () => {
+      googlePackage.serverless.service.functions = {
+        func1: {
+          handler: 'func1',
+          events: [{ http: 'foo' }],
+        },
+      };
+      googlePackage.serverless.service.provider.environment = {
+        TEST_VAR: true,
+      };
+
+      expect(() => googlePackage.compileFunctions()).toThrow(Error);
+    });
+
     it('should set the environment variables based on the function configuration', () => {
       googlePackage.serverless.service.functions = {
         func1: {
           handler: 'func1',
           environment: {
             TEST_VAR: 'test',
+            INT_VAR: 1,
+            FLOAT_VAR: 3.141,
           },
           events: [{ http: 'foo' }],
         },
@@ -393,6 +453,8 @@ describe('CompileFunctions', () => {
             availableMemoryMb: 256,
             environmentVariables: {
               TEST_VAR: 'test',
+              INT_VAR: '1',
+              FLOAT_VAR: '3.141',
             },
             timeout: '60s',
             sourceArchiveUrl: 'gs://sls-my-service-dev-12345678/some-path/artifact.zip',
@@ -421,6 +483,8 @@ describe('CompileFunctions', () => {
       };
       googlePackage.serverless.service.provider.environment = {
         TEST_VAR: 'test',
+        INT_VAR: 1,
+        FLOAT_VAR: 3.141,
       };
 
       const compiledResources = [
@@ -435,6 +499,8 @@ describe('CompileFunctions', () => {
             availableMemoryMb: 256,
             environmentVariables: {
               TEST_VAR: 'test',
+              INT_VAR: '1',
+              FLOAT_VAR: '3.141',
             },
             timeout: '60s',
             sourceArchiveUrl: 'gs://sls-my-service-dev-12345678/some-path/artifact.zip',