diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index 84c555b890..d1aa32be48 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -895,8 +895,16 @@ bool buf_freeall(buf_T *buf, int flags)
     unblock_autocmds();
   }
 
+  linenr_T count = buf->b_ml.ml_line_count;
   ml_close(buf, true);              // close and delete the memline/memfile
   buf->b_ml.ml_line_count = 0;      // no lines in buffer
+
+  // Ensure marks are adjusted for cleared buffer in case buffer not on disk:
+  // if it is reloaded the buffer will be empty.
+  if (bt_nofilename(buf) && !exiting) {
+    mark_adjust_buf(buf, 1, count, MAXLNUM, -count, false, kMarkAdjustNormal, kExtmarkNoUndo);
+  }
+
   if ((flags & BFA_KEEP_UNDO) == 0) {
     // free the memory allocated for undo
     // and reset all undo information
diff --git a/test/functional/api/extmark_spec.lua b/test/functional/api/extmark_spec.lua
index 3245eba80c..911d9fb0bf 100644
--- a/test/functional/api/extmark_spec.lua
+++ b/test/functional/api/extmark_spec.lua
@@ -1959,6 +1959,16 @@ describe('API/extmarks', function()
       },
     }
   end)
+
+  it('are invalidated when "nofile" buffer is unloaded', function()
+    local buf = api.nvim_create_buf(false, true)
+    api.nvim_buf_set_name(buf, 'foo')
+    api.nvim_buf_set_lines(buf, 0, 0, false, { 'foo', 'bar' })
+    local id = api.nvim_buf_set_extmark(buf, ns, 1, 0, { invalidate = true })
+    api.nvim_buf_delete(buf, { unload = true })
+    local mark = { 0, 0, { invalid = true, invalidate = true, ns_id = 3, right_gravity = true } }
+    eq(mark, api.nvim_buf_get_extmark_by_id(buf, ns, id, { details = true }))
+  end)
 end)
 
 describe('Extmarks buffer api with many marks', function()