diff --git a/README.md b/README.md
index 0470449364..f97853292a 100644
--- a/README.md
+++ b/README.md
@@ -157,6 +157,18 @@ is recommended.
 Arguments can be passed to `gn` by setting the `$GN_ARGS` environmental
 variable.
 
+For Linux targets, `rusty_v8` now defaults to defining
+`V8_TLS_USED_IN_LIBRARY` via GN args when building from source so the produced
+static archive can be linked into downstream `cdylib`/shared-library targets.
+The default injected argument is:
+
+```bash
+GN_ARGS='extra_cflags=["-DV8_TLS_USED_IN_LIBRARY"]'
+```
+
+Linux prebuilt release archives published by this repository are built with
+this shared-library-compatible TLS mode.
+
 Env vars used in when building from source: `SCCACHE`, `CCACHE`, `GN`, `NINJA`,
 `CLANG_BASE_PATH`, `GN_ARGS`
 
diff --git a/build.rs b/build.rs
index b7af326355..a8e7af7c5b 100644
--- a/build.rs
+++ b/build.rs
@@ -346,10 +346,20 @@ fn build_v8(is_asan: bool) {
     println!("cargo:warning=Not using sccache or ccache");
   }
 
-  if let Ok(args) = env::var("GN_ARGS") {
-    for arg in args.split_whitespace() {
-      gn_args.push(arg.to_string());
+  // Use the shared-library-safe TLS mode by default on Linux so downstream
+  // cdylibs can link rusty_v8 archives. Skip injection when GN_ARGS already
+  // sets V8_TLS_USED_IN_LIBRARY.
+  let mut should_inject_tls_library_define = target_os == "linux";
+  if let Ok(raw_gn_args) = env::var("GN_ARGS")
+    && !raw_gn_args.trim().is_empty()
+  {
+    if raw_gn_args.contains("V8_TLS_USED_IN_LIBRARY") {
+      should_inject_tls_library_define = false;
     }
+    gn_args.push(raw_gn_args);
+  }
+  if should_inject_tls_library_define {
+    gn_args.push(r#"extra_cflags=["-DV8_TLS_USED_IN_LIBRARY"]"#.to_string());
   }
   // cross-compilation setup
   if target_arch == "aarch64" {