diff --git a/.bazelversion b/.bazelversion
index 19b860c18..f22d756da 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-6.4.0
+6.5.0
diff --git a/CHANGELOG.md b/CHANGELOG.md
index d9dbdda4f..bc612e838 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,12 +8,13 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/).
 ### Changed
 
 * Use ghc 9.4.6 by default
+* Use Bazel 6.5.0 by default (See https://github.com/tweag/rules_haskell/pull/2117)
 
 ## [0.19] 2024-02-5
 
 [0.19]: https://github.com/tweag/rules_haskell/compare/v0.18...v0.19
 
-### Highlights 
+### Highlights
 
 * Fix toolchain libraries creation when using `ghcWithPackages` (https://github.com/tweag/rules_haskell/pull/2098)
 
@@ -21,7 +22,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/).
 
 * Ghc 9.6.4 (https://github.com/tweag/rules_haskell/pull/2108)
 
-### Changed 
+### Changed
 
 * Upgrade  `rules_sh` to `0.4.0` (https://github.com/tweag/rules_haskell/pull/2103)
 
diff --git a/haskell/private/versions.bzl b/haskell/private/versions.bzl
index cd43259b7..54f3f5393 100644
--- a/haskell/private/versions.bzl
+++ b/haskell/private/versions.bzl
@@ -16,7 +16,7 @@
 SUPPORTED_BAZEL_VERSIONS = [
     "6.0.0",
     "6.3.2",
-    "6.4.0",
+    "6.5.0",
 ]
 
 SUPPORTED_NIXPKGS_BAZEL_PACKAGES = [
diff --git a/nixpkgs/nixos-unstable.nix b/nixpkgs/nixos-unstable.nix
new file mode 100644
index 000000000..4b3e23af6
--- /dev/null
+++ b/nixpkgs/nixos-unstable.nix
@@ -0,0 +1,10 @@
+{ ... }@args:
+let
+  # 2024-04-27
+  sha256 = "sha256:1iy5vigbw2dx7rhzmsszc7d87sw545f0vw4kcwxk3mazxg9qrzgl";
+  rev = "2b1f64b358f2cab62617f26b3870fd0ee375d848";
+in
+import (fetchTarball {
+  inherit sha256;
+  url = "https://github.com/NixOS/nixpkgs/archive/${rev}.tar.gz";
+}) args
diff --git a/rules_haskell_tests/MODULE.bazel b/rules_haskell_tests/MODULE.bazel
index 6167a00b9..22fd99523 100644
--- a/rules_haskell_tests/MODULE.bazel
+++ b/rules_haskell_tests/MODULE.bazel
@@ -115,7 +115,7 @@ use_repo(
     "bazel_6",
     "build_bazel_bazel_6_0_0",
     "build_bazel_bazel_6_3_2",
-    "build_bazel_bazel_6_4_0",
+    "build_bazel_bazel_6_5_0",
     "glibc_locales",
     "linux_amd64_asterius-toolchain",
     "nixpkgs_config_cc",
@@ -126,6 +126,7 @@ use_repo(
     "nixpkgs_go_sdk_toolchains",
     "nixpkgs_lz4",
     "nixpkgs_python_toolchain",
+    "nixpkgs_unstable",
     "toolchains_libraries",
     "zlib.dev",
 )
diff --git a/rules_haskell_tests/non_module_deps_1.bzl b/rules_haskell_tests/non_module_deps_1.bzl
index 43e63ee3e..8ae5158fb 100644
--- a/rules_haskell_tests/non_module_deps_1.bzl
+++ b/rules_haskell_tests/non_module_deps_1.bzl
@@ -58,6 +58,12 @@ def repositories(*, bzlmod):
         nix_file = "//nixpkgs:default.nix",
     )
 
+    # TODO switch back to nixpkgs_default once bazel_* matches the version in .bazelversion
+    nixpkgs_local_repository(
+        name = "nixpkgs_unstable",
+        nix_file = "//nixpkgs:nixos-unstable.nix",
+    )
+
     nixpkgs_package(
         name = "glibc_locales",
         attribute_path = "glibcLocales",
diff --git a/rules_haskell_tests/tests/integration_testing/dependencies.bzl b/rules_haskell_tests/tests/integration_testing/dependencies.bzl
index c94bbd7f3..b4b18af0b 100644
--- a/rules_haskell_tests/tests/integration_testing/dependencies.bzl
+++ b/rules_haskell_tests/tests/integration_testing/dependencies.bzl
@@ -11,7 +11,8 @@ def integration_testing_bazel_binaries():
     for package in SUPPORTED_NIXPKGS_BAZEL_PACKAGES:
         nixpkgs_package(
             name = package,
-            repository = "@nixpkgs_default",
+            # TODO switch back to nixpkgs_default once bazel_* matches the version in .bazelversion
+            repository = "@nixpkgs_unstable",
             build_file_content = """\
 filegroup(
     name = "bazel_bin",
diff --git a/shell.nix b/shell.nix
index 38a21a923..f6db1c936 100644
--- a/shell.nix
+++ b/shell.nix
@@ -3,6 +3,8 @@
 with pkgs;
 
 let
+  nixos-unstable = import ./nixpkgs/nixos-unstable.nix { };
+
   macOS-security =
     # make `/usr/bin/security` available in `PATH`, which is needed for stack
     # on darwin which calls this binary to find certificates
@@ -42,7 +44,8 @@ mkShell {
   ++ lib.optionals docTools [ graphviz python39Packages.sphinx zip unzip ]
   ++ lib.optional stdenv.isDarwin macOS-security;
 
-  packages = [ bazel_6 ];
+  # TODO switch back to default nixpkgs once bazel_* matches the version in .bazelversion
+  packages = [ nixos-unstable.bazel_6 ];
 
   shellHook = ''
     # Add nix config flags to .bazelrc.local.