diff --git a/include/winbase.h b/include/winbase.h
index 2d01dcb606b..7b7f9f26bd2 100644
--- a/include/winbase.h
+++ b/include/winbase.h
@@ -1736,6 +1736,21 @@ typedef enum _PROC_THREAD_ATTRIBUTE_NUM
 #define SYMBOLIC_LINK_FLAG_DIRECTORY (0x1)
 #define VALID_SYMBOLIC_LINK_FLAGS SYMBOLIC_LINK_FLAG_DIRECTORY
 
+typedef struct _STARTUPINFOEXA
+{
+    STARTUPINFOA StartupInfo;
+    LPPROC_THREAD_ATTRIBUTE_LIST lpAttributeList;
+} STARTUPINFOEXA, *LPSTARTUPINFOEXA;
+
+typedef struct _STARTUPINFOEXW
+{
+    STARTUPINFOW StartupInfo;
+    LPPROC_THREAD_ATTRIBUTE_LIST lpAttributeList;
+} STARTUPINFOEXW, *LPSTARTUPINFOEXW;
+
+DECL_WINELIB_TYPE_AW(STARTUPINFOEX)
+DECL_WINELIB_TYPE_AW(LPSTARTUPINFOEX)
+
 typedef void *PUMS_CONTEXT;
 typedef void *PUMS_COMPLETION_LIST;
 typedef PRTL_UMS_SCHEDULER_ENTRY_POINT PUMS_SCHEDULER_ENTRY_POINT;