diff --git a/main.tf b/main.tf
index 59cc6a0..3335f22 100644
--- a/main.tf
+++ b/main.tf
@@ -59,6 +59,7 @@ resource "aws_lambda_function" "main_s3" {
   timeout                        = "${var.timeout}"
   role                           = "${aws_iam_role.main.arn}"
   reserved_concurrent_executions = "${var.reserved_concurrent_executions}"
+  source_code_hash               = "${var.source_code_hash}"
 
   environment {
     variables = "${var.environment}"
@@ -85,6 +86,7 @@ resource "aws_lambda_function" "vpc_s3" {
   timeout                        = "${var.timeout}"
   role                           = "${aws_iam_role.main.arn}"
   reserved_concurrent_executions = "${var.reserved_concurrent_executions}"
+  source_code_hash               = "${var.source_code_hash}"
 
   vpc_config {
     subnet_ids         = ["${var.subnet_ids}"]
diff --git a/variables.tf b/variables.tf
index 39a6ad4..af3ebc8 100644
--- a/variables.tf
+++ b/variables.tf
@@ -89,3 +89,8 @@ variable "reserved_concurrent_executions" {
   description = "The amount of reserved concurrent executions for this lambda function. A value of 0 disables lambda from being triggered and -1 removes any concurrency limitations. Defaults to Unreserved Concurrency Limits -1"
   default     = -1
 }
+
+variable "source_code_hash" {
+  description = "Used to trigger updates. Must be set to a base64-encoded SHA256 hash of the package file specified with either filename or s3_key."
+  default     = ""
+}