diff --git a/aws-lc-fips-sys/builder/cmake_builder.rs b/aws-lc-fips-sys/builder/cmake_builder.rs
index a98d81e953b..865a5cdb25f 100644
--- a/aws-lc-fips-sys/builder/cmake_builder.rs
+++ b/aws-lc-fips-sys/builder/cmake_builder.rs
@@ -3,8 +3,8 @@
 
 use crate::OutputLib::{Crypto, RustWrapper, Ssl};
 use crate::{
-    cargo_env, execute_command, is_no_asm, option_env, target, target_arch, target_os,
-    target_vendor, OutputLibType,
+    cargo_env, emit_warning, execute_command, is_no_asm, option_env, target, target_arch,
+    target_env, target_os, target_underscored, target_vendor, OutputLibType,
 };
 use std::collections::HashMap;
 use std::env;
@@ -111,17 +111,6 @@ impl CmakeBuilder {
             cmake_cfg.define("CMAKE_BUILD_TYPE", "debug");
         }
 
-        if target_os() == "windows" {
-            cmake_cfg.generator("Ninja");
-            let env_map = self
-                .collect_vcvarsall_bat()
-                .map_err(|x| panic!("{}", x))
-                .unwrap();
-            for (key, value) in env_map {
-                cmake_cfg.env(key, value);
-            }
-        }
-
         if let Some(prefix) = &self.build_prefix {
             cmake_cfg.define("BORINGSSL_PREFIX", format!("{prefix}_"));
             let include_path = self.manifest_dir.join("generated-include");
@@ -149,7 +138,9 @@ impl CmakeBuilder {
         }
 
         // Allow environment to specify CMake toolchain.
-        if option_env("CMAKE_TOOLCHAIN_FILE").is_some() {
+        if option_env("CMAKE_TOOLCHAIN_FILE").is_some()
+            || option_env(format!("CMAKE_TOOLCHAIN_FILE_{}", target_underscored())).is_some()
+        {
             return cmake_cfg;
         }
 
@@ -165,6 +156,31 @@ impl CmakeBuilder {
             }
         }
 
+        if target_os() == "windows" {
+            cmake_cfg.generator("Ninja");
+            let env_map = self
+                .collect_vcvarsall_bat()
+                .map_err(|x| panic!("{}", x))
+                .unwrap();
+            for (key, value) in env_map {
+                cmake_cfg.env(key, value);
+            }
+        }
+
+        if target_env() == "ohos" {
+            const OHOS_NDK_HOME: &str = "OHOS_NDK_HOME";
+            if let Ok(ndk) = env::var(OHOS_NDK_HOME) {
+                cmake_cfg.define(
+                    "CMAKE_TOOLCHAIN_FILE",
+                    format!("{ndk}/native/build/cmake/ohos.toolchain.cmake"),
+                );
+                cmake_cfg.define("CMAKE_C_FLAGS", "-Wno-unused-command-line-argument");
+                cmake_cfg.define("CMAKE_CXX_FLAGS", "-Wno-unused-command-line-argument");
+            } else {
+                emit_warning(format!("{OHOS_NDK_HOME} not set!").as_str());
+            }
+        }
+
         cmake_cfg
     }
 
diff --git a/aws-lc-fips-sys/builder/main.rs b/aws-lc-fips-sys/builder/main.rs
index f38a1605524..da6de18856a 100644
--- a/aws-lc-fips-sys/builder/main.rs
+++ b/aws-lc-fips-sys/builder/main.rs
@@ -249,6 +249,11 @@ fn target() -> String {
     cargo_env("TARGET")
 }
 
+#[allow(unused)]
+fn target_underscored() -> String {
+    target().replace('-', "_")
+}
+
 fn out_dir() -> PathBuf {
     PathBuf::from(cargo_env("OUT_DIR"))
 }
diff --git a/aws-lc-sys/builder/cmake_builder.rs b/aws-lc-sys/builder/cmake_builder.rs
index 910b8afc91f..eeeacb74019 100644
--- a/aws-lc-sys/builder/cmake_builder.rs
+++ b/aws-lc-sys/builder/cmake_builder.rs
@@ -3,8 +3,8 @@
 
 use crate::OutputLib::{Crypto, RustWrapper, Ssl};
 use crate::{
-    cargo_env, execute_command, is_no_asm, option_env, target, target_arch, target_env, target_os,
-    target_vendor, OutputLibType,
+    cargo_env, emit_warning, execute_command, is_no_asm, option_env, target, target_arch,
+    target_env, target_os, target_underscored, target_vendor, OutputLibType,
 };
 use std::env;
 use std::ffi::OsStr;
@@ -128,7 +128,9 @@ impl CmakeBuilder {
         }
 
         // Allow environment to specify CMake toolchain.
-        if option_env("CMAKE_TOOLCHAIN_FILE").is_some() {
+        if option_env("CMAKE_TOOLCHAIN_FILE").is_some()
+            || option_env(format!("CMAKE_TOOLCHAIN_FILE_{}", target_underscored())).is_some()
+        {
             return cmake_cfg;
         }
 
@@ -151,16 +153,13 @@ impl CmakeBuilder {
                 cmake_cfg.define("CMAKE_SYSTEM_PROCESSOR", "x86_64");
             }
         }
+
         if (target_env() != "msvc") && test_ninja_command() {
             // Use Ninja if available
             cmake_cfg.generator("Ninja");
         }
 
-        if target_os() == "windows"
-            && target_arch() == "aarch64"
-            && target_env() == "msvc"
-            && option_env("CMAKE_TOOLCHAIN_FILE_aarch64_pc_windows_msvc").is_none()
-        {
+        if target_underscored() == "aarch64_pc_windows_msvc" {
             cmake_cfg.generator("Ninja");
             cmake_cfg.define("CMAKE_C_COMPILER", "clang-cl");
             cmake_cfg.define("CMAKE_CXX_COMPILER", "clang-cl");
@@ -175,6 +174,20 @@ impl CmakeBuilder {
             }
         }
 
+        if target_env() == "ohos" {
+            const OHOS_NDK_HOME: &str = "OHOS_NDK_HOME";
+            if let Ok(ndk) = env::var(OHOS_NDK_HOME) {
+                cmake_cfg.define(
+                    "CMAKE_TOOLCHAIN_FILE",
+                    format!("{ndk}/native/build/cmake/ohos.toolchain.cmake"),
+                );
+                cmake_cfg.define("CMAKE_C_FLAGS", "-Wno-unused-command-line-argument");
+                cmake_cfg.define("CMAKE_CXX_FLAGS", "-Wno-unused-command-line-argument");
+            } else {
+                emit_warning(format!("{OHOS_NDK_HOME} not set!").as_str());
+            }
+        }
+
         cmake_cfg
     }
 
diff --git a/aws-lc-sys/builder/main.rs b/aws-lc-sys/builder/main.rs
index 27ed94cfb67..866d2055b89 100644
--- a/aws-lc-sys/builder/main.rs
+++ b/aws-lc-sys/builder/main.rs
@@ -248,6 +248,11 @@ fn target() -> String {
     cargo_env("TARGET")
 }
 
+#[allow(unused)]
+fn target_underscored() -> String {
+    target().replace('-', "_")
+}
+
 fn out_dir() -> PathBuf {
     PathBuf::from(cargo_env("OUT_DIR"))
 }