diff --git a/doc/manual/rl-next/shorter-build-dir-names.md b/doc/manual/rl-next/shorter-build-dir-names.md
new file mode 100644
index 00000000000..e87fa5d04fb
--- /dev/null
+++ b/doc/manual/rl-next/shorter-build-dir-names.md
@@ -0,0 +1,6 @@
+---
+synopsis: "Temporary build directories no longer include derivation names"
+prs: [13839]
+---
+
+Temporary build directories created during derivation builds no longer include the derivation name in their path to avoid build failures when the derivation name is too long. This change ensures predictable prefix lengths for build directories under `/nix/var/nix/builds`.
\ No newline at end of file
diff --git a/src/libstore/unix/build/derivation-builder.cc b/src/libstore/unix/build/derivation-builder.cc
index 1c497adf275..5f9dafb5711 100644
--- a/src/libstore/unix/build/derivation-builder.cc
+++ b/src/libstore/unix/build/derivation-builder.cc
@@ -736,7 +736,7 @@ void DerivationBuilderImpl::startBuilder()
 
     /* Create a temporary directory where the build will take
        place. */
-    topTmpDir = createTempDir(buildDir, "nix-build-" + std::string(drvPath.name()), 0700);
+    topTmpDir = createTempDir(buildDir, "nix", 0700);
     setBuildTmpDir();
     assert(!tmpDir.empty());
 
diff --git a/tests/functional/check.sh b/tests/functional/check.sh
index a1c6decf5b5..26050613872 100755
--- a/tests/functional/check.sh
+++ b/tests/functional/check.sh
@@ -52,10 +52,10 @@ test_custom_build_dir() {
   nix-build check.nix -A failed --argstr checkBuildId "$checkBuildId" \
       --no-out-link --keep-failed --option build-dir "$TEST_ROOT/custom-build-dir" 2> "$TEST_ROOT/log" || status=$?
   [ "$status" = "100" ]
-  [[ 1 == "$(count "$customBuildDir/nix-build-"*)" ]]
-  local buildDir=("$customBuildDir/nix-build-"*)
+  [[ 1 == "$(count "$customBuildDir/nix-"*)" ]]
+  local buildDir=("$customBuildDir/nix-"*)
   if [[ "${#buildDir[@]}" -ne 1 ]]; then
-    echo "expected one nix-build-* directory, got: ${buildDir[*]}" >&2
+    echo "expected one nix-* directory, got: ${buildDir[*]}" >&2
     exit 1
   fi
   if [[ -e ${buildDir[*]}/build ]]; then
diff --git a/tests/nixos/user-sandboxing/default.nix b/tests/nixos/user-sandboxing/default.nix
index 3f6b575b035..d6899140ad0 100644
--- a/tests/nixos/user-sandboxing/default.nix
+++ b/tests/nixos/user-sandboxing/default.nix
@@ -104,8 +104,8 @@ in
 
           # Wait for the build to be ready
           # This is OK because it runs as root, so we can access everything
-          machine.wait_until_succeeds("stat /nix/var/nix/builds/nix-build-open-build-dir.drv-*/build/syncPoint")
-          dir = machine.succeed("ls -d /nix/var/nix/builds/nix-build-open-build-dir.drv-*").strip()
+          machine.wait_until_succeeds("stat /nix/var/nix/builds/nix-*/build/syncPoint")
+          dir = machine.succeed("ls -d /nix/var/nix/builds/nix-*").strip()
 
           # But Alice shouldn't be able to access the build directory
           machine.fail(f"su alice -c 'ls {dir}/build'")
@@ -125,8 +125,8 @@ in
                 args = [ (builtins.storePath "${create-hello-world}") ];
             }' >&2 &
           """.strip())
-          machine.wait_until_succeeds("stat /nix/var/nix/builds/nix-build-innocent.drv-*/build/syncPoint")
-          dir = machine.succeed("ls -d /nix/var/nix/builds/nix-build-innocent.drv-*").strip()
+          machine.wait_until_succeeds("stat /nix/var/nix/builds/nix-*/build/syncPoint")
+          dir = machine.succeed("ls -d /nix/var/nix/builds/nix-*").strip()
 
           # The build ran as `nixbld1` (which is the only build user on the
           # machine), but a process running as `nixbld1` outside the sandbox