diff --git a/terraform/application/database.tf b/terraform/application/database.tf
index 25dc1ed..a2f3c32 100644
--- a/terraform/application/database.tf
+++ b/terraform/application/database.tf
@@ -11,5 +11,5 @@ module "postgres" {
   use_azure                   = var.deploy_azure_backing_services
   azure_enable_monitoring     = var.enable_monitoring
   azure_enable_backup_storage = var.enable_postgres_backup_storage
-  server_version              = "16"
+  server_version              = var.postgres_server_version
 }
diff --git a/terraform/application/variables.tf b/terraform/application/variables.tf
index fed85b8..3abad58 100644
--- a/terraform/application/variables.tf
+++ b/terraform/application/variables.tf
@@ -45,6 +45,11 @@ variable "enable_postgres_backup_storage" {
   default     = false
   description = "Create a storage account to store database dumps"
 }
+variable "postgres_server_version" {
+  type        = string
+  description = "Version of PostgreSQL to use for PostgreSQL flexible server"
+  default     = "18"
+}
 variable "docker_image" {
   type        = string
   description = "Docker image full name to identify it in the registry. Includes docker registry, repository and tag e.g.: ghcr.io/dfe-digital/teacher-pay-calculator:673f6309fd0c907014f44d6732496ecd92a2bcd0"