diff --git a/doc/manual/process-includes.sh b/doc/manual/process-includes.sh
index 51ac67acb..b35a0d307 100755
--- a/doc/manual/process-includes.sh
+++ b/doc/manual/process-includes.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/usr/bin/env bash
 
 set -euo pipefail
 
diff --git a/doc/manual/render-manpage.sh b/doc/manual/render-manpage.sh
index 7d83253cb..65a9c124e 100755
--- a/doc/manual/render-manpage.sh
+++ b/doc/manual/render-manpage.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/usr/bin/env bash
 
 set -euo pipefail
 
diff --git a/maintainers/buildtime_report.sh b/maintainers/buildtime_report.sh
index 54ce75eb5..3f17ef5ce 100755
--- a/maintainers/buildtime_report.sh
+++ b/maintainers/buildtime_report.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/usr/bin/env bash
 
 # Generates a report of build time based on a meson build using -ftime-trace in
 # Clang.
diff --git a/package.nix b/package.nix
index 475827bd7..f75454254 100644
--- a/package.nix
+++ b/package.nix
@@ -302,6 +302,9 @@ stdenv.mkDerivation (finalAttrs: {
       else
         appendToVar configureFlags "--disable-tests"
       fi
+
+      # Fix up /usr/bin/env shebangs relied on by the build
+      patchShebangs --build tests/ doc/manual/
     '';
 
   mesonBuildType = "debugoptimized";
diff --git a/tests/functional/install-darwin.sh b/tests/functional/install-darwin.sh
index ea2b75323..c785437f4 100755
--- a/tests/functional/install-darwin.sh
+++ b/tests/functional/install-darwin.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/usr/bin/env bash
 
 set -eux
 
diff --git a/tests/functional/nix-daemon-untrusting.sh b/tests/functional/nix-daemon-untrusting.sh
index bcdb70989..22f0d45ae 100755
--- a/tests/functional/nix-daemon-untrusting.sh
+++ b/tests/functional/nix-daemon-untrusting.sh
@@ -1,3 +1,3 @@
-#!/bin/sh
+#!/usr/bin/env bash
 
 exec nix-daemon --force-untrusted "$@"
diff --git a/tests/functional/push-to-store-old.sh b/tests/functional/push-to-store-old.sh
index 4187958b2..21f55b70e 100755
--- a/tests/functional/push-to-store-old.sh
+++ b/tests/functional/push-to-store-old.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/usr/bin/env bash
 
 set -x
 set -e
diff --git a/tests/functional/push-to-store.sh b/tests/functional/push-to-store.sh
index 9e4e475e0..fe551179e 100755
--- a/tests/functional/push-to-store.sh
+++ b/tests/functional/push-to-store.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/usr/bin/env bash
 
 set -x
 set -e