diff --git a/.github/workflows/buildbsd.yml b/.github/workflows/buildbsd.yml
new file mode 100644
index 0000000..4851278
--- /dev/null
+++ b/.github/workflows/buildbsd.yml
@@ -0,0 +1,64 @@
+name: build and test bsd
+
+on:
+  push:
+    branches: [ master, dev ]
+
+  pull_request:
+    branches: [ master ]
+
+# The BSDs use the same sysv_amd64 ABI as Linux, so these jobs build and test
+# the existing sources rather than producing an additional library artifact.
+# Each job runs in a real VM on the ubuntu-latest runner; GNU make is required
+# because the Makefile uses GNU make syntax, while the BSD base system make
+# is bmake.
+
+jobs:
+
+  build-freebsd:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v6.0.2
+    - name: build and test
+      uses: vmactions/freebsd-vm@v1
+      with:
+        usesh: true
+        cache-after-prepare: true
+        prepare: |
+          pkg install -y gmake
+        run: |
+          set -ex
+          gmake all
+          gmake test
+
+  build-openbsd:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v6.0.2
+    - name: build and test
+      uses: vmactions/openbsd-vm@v1
+      with:
+        usesh: true
+        cache-after-prepare: true
+        prepare: |
+          pkg_add -I gmake
+        run: |
+          set -ex
+          gmake all
+          gmake test
+
+  build-netbsd:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v6.0.2
+    - name: build and test
+      uses: vmactions/netbsd-vm@v1
+      with:
+        usesh: true
+        cache-after-prepare: true
+        prepare: |
+          /usr/sbin/pkg_add gmake
+        run: |
+          set -ex
+          gmake all
+          gmake test
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 80fb048..49f2c42 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+- FreeBSD, OpenBSD and NetBSD (amd64, `sysv_amd64` ABI) are built and tested on every commit by a new `build and test bsd` workflow.
+
+### Fixed
+- ABI detection now works on the BSDs: `tools/abiname.sh` used a `mktemp` template with three `X`s, which BSD `mktemp(1)` rejects.
+
 ## [1.2.5] - 2026-06-23
 
 ### Changed
diff --git a/README.md b/README.md
index 1b6326d..1e770b8 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,5 @@
 [![build test and commit](https://github.com/stackless-dev/stackman/actions/workflows/buildcommit.yml/badge.svg)](https://github.com/stackless-dev/stackman/actions/workflows/buildcommit.yml)
+[![build and test bsd](https://github.com/stackless-dev/stackman/actions/workflows/buildbsd.yml/badge.svg)](https://github.com/stackless-dev/stackman/actions/workflows/buildbsd.yml)
 
 
 ```
@@ -101,9 +102,16 @@ calling convention, plus archive format:
    - win_x86 (32-bit)
    - win_x64 (64-bit)
    - win_arm64 (64-bit ARM)
+ - **FreeBSD, OpenBSD, NetBSD (System V ABI)**
+   - sysv_amd64 (64-bit x86_64)
 
 All platforms are automatically built and tested by GitHub Actions CI on every commit.
 
+The BSDs share the `sysv_amd64` ABI with Linux and therefore need no separate
+assembly implementation or pre-built library; they are built and tested from
+source by the `build and test bsd` workflow.  Note that the Makefile requires
+GNU make, which on the BSDs is `gmake` rather than the base system `make`.
+
 ### Supported toolchains:
 
  - Gnu C
diff --git a/tools/abiname.sh b/tools/abiname.sh
index 472c012..d4fd663 100644
--- a/tools/abiname.sh
+++ b/tools/abiname.sh
@@ -61,7 +61,8 @@ abi_from_target_triple() {
 mkdir -p "${here}/tmp"
 # Clean up any stale temp files first
 rm -f "${here}/tmp"/abiname*.c "${here}/tmp"/abiname*.c.out
-tmp=$(mktemp "${here}/tmp/abinameXXX.c")
+# BSD mktemp(1) requires at least six trailing Xs; GNU mktemp accepts them too.
+tmp=$(mktemp "${here}/tmp/abinameXXXXXX.c")
 
 #1 create the preprocessed file
 CC=${1:-cc}