diff --git a/include/dmosi.h b/include/dmosi.h
index 8c50ad7..2df38ef 100644
--- a/include/dmosi.h
+++ b/include/dmosi.h
@@ -372,6 +372,16 @@ typedef struct {
     uint64_t runtime_ms;        /**< Thread runtime in milliseconds */
 } dmosi_thread_info_t;
 
+/**
+ * @brief Extra stack bytes reserved for thread and module startup overhead
+ *
+ * The thread entry wrapper and module loading infrastructure consume stack
+ * before the module's own main function is invoked. This constant accounts
+ * for that overhead so that the effective stack available to the module
+ * matches the size declared in its header.
+ */
+#define DMOSI_THREAD_STACK_OVERHEAD 512
+
 /**
  * @brief Create a thread
  *
diff --git a/src/dmosi.c b/src/dmosi.c
index 8d65cf1..4d83d3f 100644
--- a/src/dmosi.c
+++ b/src/dmosi.c
@@ -593,11 +593,12 @@ static Dmod_Pid_t dmod_spawn_module_internal(Dmod_Context_t* Context, int argc,
     spawn_args->argv = argv;
     spawn_args->process = new_process;
 
-    // Get stack size from Context header
+    // Get stack size from Context header and add overhead for thread/module startup
     uint64_t stack_size = Dmod_GetStackSize(Context);
     if (stack_size == 0) {
         stack_size = DMOSI_DEFAULT_STACK_SIZE;
     }
+    stack_size += DMOSI_THREAD_STACK_OVERHEAD;
 
     // Inherit priority from current thread
     int priority = dmosi_thread_get_priority(NULL);