diff --git a/repos/base-hw/src/core/spec/x86_64/kernel/crt0.s b/repos/base-hw/src/core/spec/x86_64/kernel/crt0.s
index 8481cb9f8..1020f23f4 100644
--- a/repos/base-hw/src/core/spec/x86_64/kernel/crt0.s
+++ b/repos/base-hw/src/core/spec/x86_64/kernel/crt0.s
@@ -54,6 +54,9 @@
 	btsl $31, %eax
 	movl %eax, %cr0
 
+	/* Set up GDT */
+	lgdt _gdt_ptr
+
 	/*
 	 * Install initial temporary environment that is replaced later by the
 	 * environment that init_main_thread creates.