diff --git a/doc/mimalloc-doc.h b/doc/mimalloc-doc.h
index 8f36750e..e923026b 100644
--- a/doc/mimalloc-doc.h
+++ b/doc/mimalloc-doc.h
@@ -558,7 +558,7 @@ mi_heap_t* mi_heap_new();
 
 /// Delete a previously allocated heap.
 /// This will release resources and migrate any
-/// still allocated blocks in this heap (efficienty)
+/// still allocated blocks in this heap (efficiency)
 /// to the default heap.
 ///
 /// If \a heap is the default heap, the default
diff --git a/docs/group__heap.html b/docs/group__heap.html
index 5f976989..e4b5340e 100644
--- a/docs/group__heap.html
+++ b/docs/group__heap.html
@@ -372,7 +372,7 @@ Functions</h2></td></tr>
 </div><div class="memdoc">
 
 <p>Delete a previously allocated heap. </p>
-<p>This will release resources and migrate any still allocated blocks in this heap (efficienty) to the default heap.</p>
+<p>This will release resources and migrate any still allocated blocks in this heap (efficiency) to the default heap.</p>
 <p>If <em>heap</em> is the default heap, the default heap is set to the backing heap. </p>
 
 </div>