diff --git a/compiler/src/main/pascal/blaise.codegen.driver.pas b/compiler/src/main/pascal/blaise.codegen.driver.pas
index 90f681a..36693c4 100644
--- a/compiler/src/main/pascal/blaise.codegen.driver.pas
+++ b/compiler/src/main/pascal/blaise.codegen.driver.pas
@@ -504,6 +504,7 @@ begin
     Units.Add('runtime.cstub');
     Units.Add('runtime.libc.linux');
     Units.Add('runtime.libc2.linux');
+    Units.Add('runtime.thread.static.linux');
   end;
 
   for I := 0 to Units.Count - 1 do
diff --git a/compiler/src/main/pascal/runtime.thread.static.linux.pas b/compiler/src/main/pascal/runtime.thread.static.linux.pas
new file mode 100644
index 0000000..c293086
--- /dev/null
+++ b/compiler/src/main/pascal/runtime.thread.static.linux.pas
@@ -0,0 +1,53 @@
+{
+  Blaise - An Object Pascal Compiler
+  Copyright (c) 2026 Graeme Geldenhuys
+  SPDX-License-Identifier: Apache-2.0 WITH Swift-exception
+  Licensed under the Apache License v2.0 with Runtime Library Exception.
+  See LICENSE file in the project root for full license terms.
+}
+
+unit runtime.thread.static.linux;
+
+// Single-threaded mutex stubs for the --static (libc-free) build.  Real threads
+// (pthread_create via clone + futex-based mutexes) are deferred to the threads
+// step of the migration (docs/linux-syscall-migration.adoc); until then a
+// static program is single-threaded, so the locks are uncontended and these
+// no-op stubs are correct.  pthread_create itself is intentionally NOT provided:
+// a static program that spawns a thread will fail to link, which is the honest
+// signal that the threads leaf is not done yet.
+//
+// DEFINES the bare pthread_mutex_* names that runtime.weak / runtime.thread
+// import via `external name`.
+
+interface
+
+function pthread_mutex_init(Mutex, Attr: Pointer): Integer;
+function pthread_mutex_lock(Mutex: Pointer): Integer;
+function pthread_mutex_unlock(Mutex: Pointer): Integer;
+function pthread_mutex_destroy(Mutex: Pointer): Integer;
+
+implementation
+
+{ All no-ops returning success: a single-threaded process never contends. }
+
+function pthread_mutex_init(Mutex, Attr: Pointer): Integer;
+begin
+  Result := 0;
+end;
+
+function pthread_mutex_lock(Mutex: Pointer): Integer;
+begin
+  Result := 0;
+end;
+
+function pthread_mutex_unlock(Mutex: Pointer): Integer;
+begin
+  Result := 0;
+end;
+
+function pthread_mutex_destroy(Mutex: Pointer): Integer;
+begin
+  Result := 0;
+end;
+
+end.