diff --git a/luna/src/Heap.cpp b/luna/src/Heap.cpp
index 2e9b686f..25623a71 100644
--- a/luna/src/Heap.cpp
+++ b/luna/src/Heap.cpp
@@ -6,6 +6,7 @@
 #include <luna/LinkedList.h>
 #include <luna/SafeArithmetic.h>
 #include <luna/ScopeGuard.h>
+#include <luna/Spinlock.h>
 #include <luna/SystemError.h>
 
 #ifdef USE_FREESTANDING
@@ -45,9 +46,10 @@ static_assert(sizeof(HeapBlock) == 48UL);
 static const isize HEAP_BLOCK_SIZE = 48;
 
 static LinkedList<HeapBlock> heap;
+static Spinlock g_heap_lock;
 
-// If we're allocating a large amount of memory, map enough pages for it, but otherwise just use the default amount of
-// pages.
+// If we're allocating a large amount of memory, map enough pages for it, but otherwise just use the default amount
+// of pages.
 static usize get_pages_for_allocation(usize bytes)
 {
     usize pages = get_blocks_from_size(bytes, PAGE_SIZE);
@@ -178,6 +180,8 @@ Result<void*> malloc_impl(usize size, bool should_scrub)
 {
     if (!size) return (void*)BLOCK_MAGIC;
 
+    ScopeLock lock(g_heap_lock);
+
     size = align_up<16>(size);
 
     Option<HeapBlock*> block = heap.first();
@@ -231,6 +235,8 @@ Result<void> free_impl(void* ptr)
     if (ptr == (void*)BLOCK_MAGIC) return {}; // This pointer was returned from a call to malloc(0)
     if (!ptr) return {};
 
+    ScopeLock lock(g_heap_lock);
+
     HeapBlock* block = get_heap_block_for_pointer(ptr);
 
     if (block->magic != BLOCK_MAGIC)
@@ -286,6 +292,8 @@ Result<void*> realloc_impl(void* ptr, usize size)
         return (void*)BLOCK_MAGIC;
     }
 
+    ScopeLock lock(g_heap_lock);
+
     HeapBlock* const block = get_heap_block_for_pointer(ptr);
 
     if (block->magic != BLOCK_MAGIC)
@@ -327,6 +335,8 @@ Result<void*> realloc_impl(void* ptr, usize size)
 
     usize old_size = block->req_size;
 
+    lock.take_over().unlock();
+
     void* const new_ptr = TRY(malloc_impl(size, false));
     memcpy(new_ptr, ptr, old_size > size ? size : old_size);
     TRY(free_impl(ptr));