diff --git a/nixos/modules/services/networking/ncps.nix b/nixos/modules/services/networking/ncps.nix
index 96f557edd41f..589d115a5632 100644
--- a/nixos/modules/services/networking/ncps.nix
+++ b/nixos/modules/services/networking/ncps.nix
@@ -97,7 +97,6 @@ let
       lock = {
         backend = cfg.cache.lock.backend;
         redis.key-prefix = cfg.cache.lock.redisKeyPrefix;
-        postgres.key-prefix = cfg.cache.lock.postgresKeyPrefix;
         download-lock-ttl = cfg.cache.lock.downloadTTL;
         lru-lock-ttl = cfg.cache.lock.lruTTL;
         retry = {
@@ -151,6 +150,14 @@ in
       "ncps"
       "dbmatePackage"
     ] "dbmate is now wrapped within ncps package, you need to override ncps to change dbmate package")
+
+    (lib.mkRemovedOptionModule [
+      "services"
+      "ncps"
+      "cache"
+      "lock"
+      "postgresKeyPrefix"
+    ] "PostgreSQL lock backend was removed upstream")
   ];
 
   options = {
@@ -285,22 +292,11 @@ in
             type = lib.types.enum [
               "local"
               "redis"
-              "postgres"
             ];
             default = "local";
             description = ''
               Lock backend to use: 'local' (single instance), 'redis'
-              (distributed), 'postgres' (distributed, requires PostgreSQL).
-
-              Advisory Locks and Connection Pools: If you use PostgreSQL as
-              your distributed lock backend, each active lock consumes a
-              dedicated connection from the pool. A single request can consume
-              up to 3 connections simultaneously.
-
-              To avoid deadlocks under concurrent load, ensure
-              {option}`services.ncps.cache.database.pool.maxOpenConns` is
-              significantly higher than your expected concurrency (at least
-              50-100 is recommended).
+              (distributed).
             '';
           };
 
@@ -313,15 +309,6 @@ in
             '';
           };
 
-          postgresKeyPrefix = lib.mkOption {
-            type = lib.types.str;
-            default = "ncps:lock:";
-            description = ''
-              Prefix for all PostgreSQL advisory lock keys (only used when
-              PostgreSQL is configured as lock backend).
-            '';
-          };
-
           downloadTTL = lib.mkOption {
             type = lib.types.str;
             default = "5m0s";
diff --git a/nixos/tests/all-tests.nix b/nixos/tests/all-tests.nix
index 11317df27c0a..9331257a6dfe 100644
--- a/nixos/tests/all-tests.nix
+++ b/nixos/tests/all-tests.nix
@@ -1049,7 +1049,6 @@ in
     imports = [ ./ncps.nix ];
     defaults.services.ncps.cache.storage.local = "/path/to/ncps";
   };
-  ncps-ha-pg = runTest ./ncps-ha-pg.nix;
   ncps-ha-pg-redis = runTest ./ncps-ha-pg-redis.nix;
   ndppd = runTest ./ndppd.nix;
   nebula-lighthouse-service = runTest ./nebula-lighthouse-service.nix;
diff --git a/nixos/tests/ncps-ha-pg.nix b/nixos/tests/ncps-ha-pg.nix
deleted file mode 100644
index f650a1bcd1ed..000000000000
--- a/nixos/tests/ncps-ha-pg.nix
+++ /dev/null
@@ -1,169 +0,0 @@
-{
-  lib,
-  pkgs,
-  ...
-}:
-let
-  # s3 creds
-  bucket = "ncps";
-  region = "us-west-1";
-  accessKey = builtins.toFile "minio-access-key" "easy-key";
-  secretKey = builtins.toFile "minio-secret-key" "easy-secret";
-
-  # pg creds
-  postgresPassword = "easypwd";
-
-  initMinio = pkgs.writeShellScriptBin "init-minio.sh" ''
-    set -euo pipefail
-
-    mc alias set local "http://127.0.0.1:9000" minioadmin minioadmin
-    mc mb local/${bucket}
-    mc admin user svcacct add --access-key "$(cat ${accessKey})" --secret-key "$(cat ${secretKey})" local minioadmin
-  '';
-
-  ncpsAttrs = hostname: {
-    services.ncps = {
-      enable = true;
-
-      analytics.reporting.enable = false;
-
-      cache = {
-        hostName = hostname;
-
-        databaseURL = "postgres://ncps:${lib.escapeURL postgresPassword}@postgres:5432/ncps?sslmode=disable";
-
-        lock.backend = "postgres";
-
-        secretKeyPath = builtins.toString (
-          pkgs.writeText "ncps-cache-key" "ncps:dcrGsrku0KvltFhrR5lVIMqyloAdo0y8vYZOeIFUSLJS2IToL7dPHSSCk/fi+PJf8EorpBn8PU7MNhfvZoI8mA=="
-        );
-
-        storage.s3 = {
-          inherit bucket region;
-
-          endpoint = "http://minio:9000";
-
-          accessKeyIdPath = accessKey;
-          secretAccessKeyPath = secretKey;
-        };
-
-        upstream = {
-          urls = [ "http://harmonia:5000" ];
-          publicKeys = [
-            "cache.example.com-1:eIGQXcGQpc00x6/XFcyacLEUmC07u4RAEHt5Y8vdglo="
-          ];
-        };
-      };
-    };
-
-    networking.firewall.allowedTCPPorts = [ 8501 ];
-  };
-in
-{
-  name = "ncps-storage-s3";
-  meta = with lib.maintainers; {
-    maintainers = [
-      aciceri
-      kalbasit
-    ];
-  };
-
-  nodes = {
-    client0 = {
-      nix.settings = {
-        substituters = lib.mkForce [ "http://ncps0:8501" ];
-        trusted-public-keys = lib.mkForce [
-          "ncps:UtiE6C+3Tx0kgpP34vjyX/BKK6QZ/D1OzDYX72aCPJg="
-        ];
-      };
-    };
-
-    client1 = {
-      nix.settings = {
-        substituters = lib.mkForce [ "http://ncps1:8501" ];
-        trusted-public-keys = lib.mkForce [
-          "ncps:UtiE6C+3Tx0kgpP34vjyX/BKK6QZ/D1OzDYX72aCPJg="
-        ];
-      };
-    };
-
-    harmonia = {
-      services.harmonia = {
-        enable = true;
-        signKeyPaths = [
-          (pkgs.writeText "cache-key" "cache.example.com-1:9FhO0w+7HjZrhvmzT1VlAZw4OSAlFGTgC24Seg3tmPl4gZBdwZClzTTHr9cVzJpwsRSYLTu7hEAQe3ljy92CWg==")
-        ];
-        settings.priority = 35;
-      };
-
-      networking.firewall.allowedTCPPorts = [ 5000 ];
-      system.extraDependencies = [ pkgs.emptyFile ];
-    };
-
-    minio = {
-      services.minio = {
-        inherit region;
-
-        enable = true;
-      };
-
-      networking.firewall.allowedTCPPorts = [ 9000 ];
-      environment.systemPackages = [
-        pkgs.minio-client
-        initMinio
-      ];
-    };
-
-    ncps0 = lib.mkMerge [
-      (ncpsAttrs "ncps0")
-      {
-        services.ncps.cache.databaseURL = lib.mkForce null;
-        services.ncps.cache.databaseURLFile = builtins.toFile "db-url" "postgres://ncps:${lib.escapeURL postgresPassword}@postgres:5432/ncps?sslmode=disable";
-      }
-    ];
-    ncps1 = ncpsAttrs "ncps1";
-
-    postgres = {
-      services.postgresql = {
-        enable = true;
-        enableTCPIP = true;
-        authentication = ''
-          host all all all scram-sha-256
-        '';
-        initialScript = pkgs.writeText "init-postgres.sql" ''
-          CREATE DATABASE "ncps" WITH ENCODING = 'UTF8';
-          CREATE ROLE "ncps" WITH LOGIN PASSWORD '${
-            builtins.replaceStrings [ "'" ] [ "''" ] postgresPassword
-          }';
-          ALTER DATABASE "ncps" OWNER TO "ncps";
-        '';
-      };
-
-      networking.firewall.allowedTCPPorts = [ 5432 ];
-    };
-  };
-
-  testScript =
-    { nodes, ... }:
-    ''
-      harmonia.start()
-      minio.start()
-      postgres.start()
-
-      minio.wait_for_unit("minio.service")
-
-      minio.wait_until_succeeds("init-minio.sh")
-
-      postgres.wait_for_unit("postgresql.service")
-
-      start_all()
-
-      harmonia.wait_for_unit("harmonia.service")
-
-      ncps0.wait_for_unit("ncps.service")
-      ncps1.wait_for_unit("ncps.service")
-
-      client0.wait_until_succeeds("curl -f http://ncps0:8501/ | grep '\"hostname\":\"${toString nodes.ncps0.services.ncps.cache.hostName}\"' >&2")
-      client1.wait_until_succeeds("curl -f http://ncps1:8501/ | grep '\"hostname\":\"${toString nodes.ncps1.services.ncps.cache.hostName}\"' >&2")
-    '';
-}
diff --git a/pkgs/by-name/nc/ncps/package.nix b/pkgs/by-name/nc/ncps/package.nix
index 0c374caa4025..902156b58c1e 100644
--- a/pkgs/by-name/nc/ncps/package.nix
+++ b/pkgs/by-name/nc/ncps/package.nix
@@ -135,7 +135,6 @@ buildGoModule (finalAttrs: {
         ncps
         ncps-custom-sqlite-directory
         ncps-custom-storage-local
-        ncps-ha-pg
         ncps-ha-pg-redis
         ;
     };