diff --git a/include/ring-core/base.h b/include/ring-core/base.h
index f1a027d1a..69cf40ca2 100644
--- a/include/ring-core/base.h
+++ b/include/ring-core/base.h
@@ -89,6 +89,9 @@
 #elif defined(__MIPSEL__) && defined(__LP64__)
 #define OPENSSL_64_BIT
 #define OPENSSL_MIPS64
+#elif defined(__s390x__)
+#define OPENSSL_64_BIT
+#define OPENSSL_S390X
 #elif defined(__wasm__)
 #define OPENSSL_32_BIT
 #else
diff --git a/mk/cargo.sh b/mk/cargo.sh
index 48ac92d71..889539be0 100755
--- a/mk/cargo.sh
+++ b/mk/cargo.sh
@@ -21,6 +21,7 @@ rustflags_self_contained="-Clink-self-contained=yes -Clinker=rust-lld"
 qemu_aarch64="qemu-aarch64 -L /usr/aarch64-linux-gnu"
 qemu_arm="qemu-arm -L /usr/arm-linux-gnueabihf"
 qemu_mipsel="qemu-mipsel -L /usr/mipsel-linux-gnu"
+qemu_s390x="qemu-s390x -L /usr/s390x-linux-gnu"
 
 # Avoid putting the Android tools in `$PATH` because there are tools in this
 # directory like `clang` that would conflict with the same-named tools that may
@@ -108,6 +109,13 @@ case $target in
       export CARGO_TARGET_X86_64_UNKNOWN_LINUX_MUSL_RUSTFLAGS="$rustflags_self_contained"
     fi
     ;;
+  s390x-unknown-linux-gnu)
+    export CC_s390x_unknown_linux_gnu=clang-$llvm_version
+    export AR_s390x_unknown_linux_gnu=llvm-ar-$llvm_version
+    export CFLAGS_s390x_unknown_linux_gnu="--sysroot=/usr/s390x-linux-gnu"
+    export CARGO_TARGET_S390X_UNKNOWN_LINUX_GNU_LINKER=s390x-linux-gnu-gcc
+    export CARGO_TARGET_S390X_UNKNOWN_LINUX_GNU_RUNNER="$qemu_s390x"
+    ;;
   wasm32-unknown-unknown)
     # The first two are only needed for when the "wasm_c" feature is enabled.
     export CC_wasm32_unknown_unknown=clang-$llvm_version
diff --git a/mk/install-build-tools.sh b/mk/install-build-tools.sh
index 2b578dd4f..3a1e15c16 100755
--- a/mk/install-build-tools.sh
+++ b/mk/install-build-tools.sh
@@ -78,6 +78,14 @@ case $target in
     libc6-dev-mipsel-cross \
     qemu-user
   ;;
+--target=s390x-unknown-linux-gnu)
+  # Clang is needed for code coverage.
+  use_clang=1
+  install_packages \
+    qemu-user \
+    gcc-s390x-linux-gnu \
+    libc6-dev-s390x-cross
+  ;;
 --target=wasm32-unknown-unknown)
   cargo install wasm-bindgen-cli --bin wasm-bindgen-test-runner
   use_clang=1