diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index 4590b86f18..7a3cf52a1a 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -4192,7 +4192,10 @@ char *vim_strsave_fnameescape(const char *const fname, const int what)
 {
 #ifdef BACKSLASH_IN_FILENAME
 # define PATH_ESC_CHARS " \t\n*?[{`%#'\"|!<"
-# define BUFFER_ESC_CHARS (" \t\n*?[`%#'\"|!<")
+// '%' and '#' are not escaped for ":buffer": it has no EX_XFILE, so they are
+// not expanded, and escaping them as "\%"/"\#" breaks buffer name matching
+// when '%'/'#' is in 'isfname' (backslash treated as a path separator).
+# define BUFFER_ESC_CHARS (" \t\n*?[`'\"|!<")
   char buf[sizeof(PATH_ESC_CHARS)];
   int j = 0;
 
diff --git a/test/old/testdir/test_buffer.vim b/test/old/testdir/test_buffer.vim
index e71907ff39..c025811b53 100644
--- a/test/old/testdir/test_buffer.vim
+++ b/test/old/testdir/test_buffer.vim
@@ -937,4 +937,19 @@ func Test_split_window_in_BufLeave_from_switching_buffer()
   bwipe! Xb
 endfunc
 
+" Switch to a buffer whose name contains '%' via completion (#20529).
+func Test_buffer_switch_to_name_with_percent()
+  CheckMSWindows
+
+  let bufnr = bufadd('Xpercent%name')
+  call setbufvar(bufnr, '&buflisted', 1)
+  call bufload(bufnr)
+  enew
+
+  call feedkeys(":b Xpercent\<Tab>\<CR>", 'xt')
+  call assert_equal(bufnr, bufnr('%'))
+
+  exe 'bwipe! ' .. bufnr
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab