diff --git a/testing/py3-cstruct/APKBUILD b/testing/py3-cstruct/APKBUILD
index 17b26e9989b936c1ebe7f5209cafc5d82ec795a9..36697ac4cdd116422d74b92370c63c2469ee465a 100644
--- a/testing/py3-cstruct/APKBUILD
+++ b/testing/py3-cstruct/APKBUILD
@@ -5,7 +5,7 @@ pkgrel=0
 pkgdesc="C-style structs for Python"
 url="https://github.com/andreax79/python-cstruct"
 license="MIT"
-arch="noarch"
+arch="noarch !s390x" # test_union_unpack test fails on s390x
 makedepends="py3-gpep517 py3-setuptools py3-wheel"
 checkdepends="py3-pytest"
 subpackages="$pkgname-pyc"