diff --git a/src/nvim/diff.c b/src/nvim/diff.c
index 17de4284ce..cc0f3b2629 100644
--- a/src/nvim/diff.c
+++ b/src/nvim/diff.c
@@ -135,6 +135,20 @@ void diff_buf_add(buf_T *buf)
   EMSGN(_("E96: Cannot diff more than %" PRId64 " buffers"), DB_COUNT);
 }
 
+///
+/// Remove all buffers to make diffs for.
+///
+static void diff_buf_clear(void)
+{
+  for (int i = 0; i < DB_COUNT; i++) {
+    if (curtab->tp_diffbuf[i] != NULL) {
+      curtab->tp_diffbuf[i] = NULL;
+      curtab->tp_diff_invalid = true;
+      diff_redraw(true);
+    }
+  }
+}
+
 /// Find buffer "buf" in the list of diff buffers for the current tab page.
 ///
 /// @param buf The buffer to find.
@@ -1175,6 +1189,11 @@ void ex_diffoff(exarg_T *eap)
     diffwin |= wp->w_p_diff;
   }
 
+  // Also remove hidden buffers from the list.
+  if (eap->forceit) {
+    diff_buf_clear();
+  }
+
   // Remove "hor" from from 'scrollopt' if there are no diff windows left.
   if (!diffwin && (vim_strchr(p_sbo, 'h') != NULL)) {
     do_cmdline_cmd("set sbo-=hor");
diff --git a/src/nvim/testdir/test_diffmode.vim b/src/nvim/testdir/test_diffmode.vim
index f40e06ff33..8ee82bd538 100644
--- a/src/nvim/testdir/test_diffmode.vim
+++ b/src/nvim/testdir/test_diffmode.vim
@@ -212,6 +212,7 @@ func Test_diffoff()
   call setline(1, ['One', '', 'Two', 'Three'])
   diffthis
   redraw
+  call assert_notequal(normattr, screenattr(1, 1))
   diffoff!
   redraw
   call assert_equal(normattr, screenattr(1, 1))
@@ -219,6 +220,42 @@ func Test_diffoff()
   bwipe!
 endfunc
 
+func Test_diffoff_hidden()
+  set diffopt=filler,foldcolumn:0
+  e! one
+  call setline(1, ['Two', 'Three'])
+  let normattr = screenattr(1, 1)
+  diffthis
+  botright vert new two
+  call setline(1, ['One', 'Four'])
+  diffthis
+  redraw
+  call assert_notequal(normattr, screenattr(1, 1))
+  set hidden
+  close
+  redraw
+  " diffing with hidden buffer two
+  call assert_notequal(normattr, screenattr(1, 1))
+  diffoff
+  redraw
+  call assert_equal(normattr, screenattr(1, 1))
+  diffthis
+  redraw
+  " still diffing with hidden buffer two
+  call assert_notequal(normattr, screenattr(1, 1))
+  diffoff!
+  redraw
+  call assert_equal(normattr, screenattr(1, 1))
+  diffthis
+  redraw
+  " no longer diffing with hidden buffer two
+  call assert_equal(normattr, screenattr(1, 1))
+
+  bwipe!
+  bwipe!
+  set hidden& diffopt&
+endfunc
+
 func Test_setting_cursor()
   new Xtest1
   put =range(1,90)
diff --git a/src/nvim/version.c b/src/nvim/version.c
index 4c0071f248..6f38776a60 100644
--- a/src/nvim/version.c
+++ b/src/nvim/version.c
@@ -652,7 +652,7 @@ static const int included_patches[] = {
   // 303,
   // 302,
   // 301,
-  // 300,
+  300,
   // 299,
   // 298,
   297,