diff --git a/aws/resource_aws_lambda_alias.go b/aws/resource_aws_lambda_alias.go
index 09d2416a4e9..110ea8cf4ea 100644
--- a/aws/resource_aws_lambda_alias.go
+++ b/aws/resource_aws_lambda_alias.go
@@ -190,8 +190,8 @@ func expandLambdaAliasRoutingConfiguration(l []interface{}) *lambda.AliasRouting
 
 	m := l[0].(map[string]interface{})
 
-	if _, ok := m["additional_version_weights"]; ok {
-		aliasRoutingConfiguration.AdditionalVersionWeights = expandFloat64Map(m)
+	if v, ok := m["additional_version_weights"]; ok {
+		aliasRoutingConfiguration.AdditionalVersionWeights = expandFloat64Map(v.(map[string]interface{}))
 	}
 
 	return aliasRoutingConfiguration
diff --git a/aws/resource_aws_lambda_alias_test.go b/aws/resource_aws_lambda_alias_test.go
index 683bf0b7317..6a6113700d4 100644
--- a/aws/resource_aws_lambda_alias_test.go
+++ b/aws/resource_aws_lambda_alias_test.go
@@ -32,6 +32,7 @@ func TestAccAWSLambdaAlias_basic(t *testing.T) {
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckAwsLambdaAliasExists("aws_lambda_alias.lambda_alias_test", &conf),
 					testAccCheckAwsLambdaAttributes(&conf),
+					testAccCheckAwsLambdaAliasRoutingConfigDoesNotExist(&conf),
 					resource.TestMatchResourceAttr("aws_lambda_alias.lambda_alias_test", "arn",
 						regexp.MustCompile(`^arn:aws:lambda:[a-z]+-[a-z]+-[0-9]+:\d{12}:function:`+funcName+`:`+aliasName+`$`)),
 				),
@@ -78,6 +79,54 @@ func TestAccAWSLambdaAlias_nameupdate(t *testing.T) {
 	})
 }
 
+func TestAccAWSLambdaAlias_routingconfig(t *testing.T) {
+	var conf lambda.AliasConfiguration
+
+	rString := acctest.RandString(8)
+	roleName := fmt.Sprintf("tf_acc_role_lambda_alias_basic_%s", rString)
+	policyName := fmt.Sprintf("tf_acc_policy_lambda_alias_basic_%s", rString)
+	attachmentName := fmt.Sprintf("tf_acc_attachment_%s", rString)
+	funcName := fmt.Sprintf("tf_acc_lambda_func_alias_basic_%s", rString)
+	aliasName := fmt.Sprintf("tf_acc_lambda_alias_basic_%s", rString)
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckAwsLambdaAliasDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccAwsLambdaAliasConfig(roleName, policyName, attachmentName, funcName, aliasName),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAwsLambdaAliasExists("aws_lambda_alias.lambda_alias_test", &conf),
+					testAccCheckAwsLambdaAttributes(&conf),
+					resource.TestMatchResourceAttr("aws_lambda_alias.lambda_alias_test", "arn",
+						regexp.MustCompile(`^arn:aws:lambda:[a-z]+-[a-z]+-[0-9]+:\d{12}:function:`+funcName+`:`+aliasName+`$`)),
+				),
+			},
+			{
+				Config: testAccAwsLambdaAliasConfigWithRoutingConfig(roleName, policyName, attachmentName, funcName, aliasName),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAwsLambdaAliasExists("aws_lambda_alias.lambda_alias_test", &conf),
+					testAccCheckAwsLambdaAttributes(&conf),
+					testAccCheckAwsLambdaAliasRoutingConfigExists(&conf),
+					resource.TestMatchResourceAttr("aws_lambda_alias.lambda_alias_test", "arn",
+						regexp.MustCompile(`^arn:aws:lambda:[a-z]+-[a-z]+-[0-9]+:\d{12}:function:`+funcName+`:`+aliasName+`$`)),
+				),
+			},
+			{
+				Config: testAccAwsLambdaAliasConfig(roleName, policyName, attachmentName, funcName, aliasName),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAwsLambdaAliasExists("aws_lambda_alias.lambda_alias_test", &conf),
+					testAccCheckAwsLambdaAttributes(&conf),
+					testAccCheckAwsLambdaAliasRoutingConfigDoesNotExist(&conf),
+					resource.TestMatchResourceAttr("aws_lambda_alias.lambda_alias_test", "arn",
+						regexp.MustCompile(`^arn:aws:lambda:[a-z]+-[a-z]+-[0-9]+:\d{12}:function:`+funcName+`:`+aliasName+`$`)),
+				),
+			},
+		},
+	})
+}
+
 func testAccCheckAwsLambdaAliasDestroy(s *terraform.State) error {
 	conn := testAccProvider.Meta().(*AWSClient).lambdaconn