diff --git a/src/internal/abi/abi_s390x.go b/src/internal/abi/abi_s390x.go
new file mode 100644
index 00000000000..9b07f27382d
--- /dev/null
+++ b/src/internal/abi/abi_s390x.go
@@ -0,0 +1,19 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build goexperiment.regabiargs
+
+package abi
+
+const (
+	// See abi_generic.go.
+
+	// R2 - R9.
+	IntArgRegs = 8
+
+	// F0 - F15
+	FloatArgRegs = 16
+
+	EffectiveFloatRegSize = 8
+)