diff --git a/modules/s3-logfile/main.tf b/modules/s3-logfile/main.tf
index 299cd5f..754701e 100644
--- a/modules/s3-logfile/main.tf
+++ b/modules/s3-logfile/main.tf
@@ -56,6 +56,7 @@ module "s3_processor" {
 
   environment_variables = {
     PARSER_TYPE         = var.parser_type
+    REGEX_PATTERN       = var.regex_pattern
     FORCE_GUNZIP        = true
     ENVIRONMENT         = var.environment
     HONEYCOMB_WRITE_KEY = var.honeycomb_api_key
diff --git a/modules/s3-logfile/variables.tf b/modules/s3-logfile/variables.tf
index d36fa47..916ea7b 100644
--- a/modules/s3-logfile/variables.tf
+++ b/modules/s3-logfile/variables.tf
@@ -82,11 +82,18 @@ variable "parser_type" {
   description = "The type of logfile to parse."
   validation {
     // ref: https://github.com/honeycombio/agentless-integrations-for-aws/blob/5f530c296035c61067a6a418d6a9ab14d34d7d79/common/common.go#L129-L153
-    condition     = contains(["alb", "elb", "s3-access", "vpc-flow", "cloudfront", "json", "keyval"], var.parser_type)
-    error_message = "parser_type must be one of the allowed values"
+    condition     = contains(["alb", "elb", "s3-access", "vpc-flow", "cloudfront", "json", "keyval", "regex"], var.parser_type)
+    error_message = "parser_type must be one of the allowed values."
   }
 }
 
+variable "regex_pattern" {
+  # This variable depends on "parser_type". In tf < 1.9, validation cannot use another variable.
+  type        = string
+  description = "Arbitrary regex pattern used to parse logfile. parser_type must be set to regex for this pattern to be used. Honeycomb columns are generated by defining named capture groups. For example, `(?P<name>[a-z]+)` would create a column called 'name' if successfully parsed."
+  default     = ""
+}
+
 variable "rename_fields" {
   type        = map(string)
   description = "Map of fields to rename, old -> new."