diff --git a/service/ptos/arch/amd64/ps/thread.c b/service/ptos/arch/amd64/ps/thread.c
index bb01c41..996ffc8 100644
--- a/service/ptos/arch/amd64/ps/thread.c
+++ b/service/ptos/arch/amd64/ps/thread.c
@@ -13,6 +13,7 @@
 #include <machine/gdt.h>
 #include <machine/lapic.h>
 #include <mm/vm.h>
+#include <mm/pm.h>
 #include <string.h>
 
 /*
@@ -32,6 +33,44 @@ ThreadAllocKStack(VOID)
     return RANGE_PTR(&StackRange);
 }
 
+/*
+ * Allocate a user stack and map it into the process
+ * address space.
+ *
+ * @Vas: Virtual address space to map to
+ */
+static UPTR
+ThreadAllocUStack(MMU_VAS *Vas)
+{
+    MM_PFN StackPfn;
+    UPTR PhysicalBase;
+    MM_RANGE MapRange;
+    PT_STATUS Status;
+
+    StackPfn = MmRequestFrame();
+    if (StackPfn == PFN_ERROR) {
+        return 0;
+    }
+
+    PhysicalBase = PFN_TO_ADDRESS(StackPfn);
+    MapRange.VirtualBase = PhysicalBase;
+    MapRange.PhysicalBase = PhysicalBase;
+    MapRange.Length = PAGESIZE;
+    Status = MmMapRange(
+        Vas,
+        &MapRange,
+        PAGE_READ | PAGE_WRITE | PAGE_USER,
+        PAGESIZE_4K
+    );
+
+    if (PT_ERROR(Status)) {
+        MmReclaimFrame(StackPfn);
+        return 0;
+    }
+
+    return PhysicalBase;
+}
+
 /*
  * Initialize a thread control block
  *
@@ -52,7 +91,18 @@ ThreadInitTcb(THREAD *Thread, TCB *Tcb, UPTR Ip)
     }
 
     Parent = Thread->Parent;
-    Thread->StackBase = (UPTR)ThreadAllocKStack();
+
+    /*
+     * Allocate a userstack or kernel stack depending on the
+     * flags set for the parent process.
+     */
+    if (ISSET(Parent->Flags, PS_USER)) {
+        Thread->StackBase = ThreadAllocUStack(&Parent->Vas);
+    } else {
+        Thread->StackBase = (UPTR)ThreadAllocKStack();
+    }
+
+    /* Did the stack allocation fail? */
     if (Thread->StackBase == 0) {
         return STATUS_NO_MEMORY;
     }