diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 7deed759b6..dedbe49605 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -1813,6 +1813,7 @@ buflisted({expr})		Number	TRUE if buffer {expr} is listed
 bufloaded({expr})		Number	TRUE if buffer {expr} is loaded
 bufname({expr})		String	Name of the buffer {expr}
 bufnr({expr} [, {create}])	Number	Number of the buffer {expr}
+bufwinid({expr})		Number	window ID of buffer {expr}
 bufwinnr({expr})		Number	window number of buffer {expr}
 byte2line({byte})		Number	line number at byte count {byte}
 byteidx({expr}, {nr})		Number	byte index of {nr}'th char in {expr}
@@ -2244,6 +2245,7 @@ arglistid([{winnr} [, {tabnr}]])
 		With {winnr} only use this window in the current tab page.
 		With {winnr} and {tabnr} use the window in the specified tab
 		page.
+		{winnr} can be the window number or the window ID.
 
 							*argv()*
 argv([{nr}])	The result is the {nr}th file in the argument list of the
@@ -2469,6 +2471,16 @@ bufnr({expr} [, {create}])
 		number necessarily exist, because ":bwipeout" may have removed
 		them.  Use bufexists() to test for the existence of a buffer.
 
+bufwinid({expr})					*bufwinid()*
+		The result is a Number, which is the window ID of the first
+		window associated with buffer {expr}.  For the use of {expr},
+		see |bufname()| above.  If buffer {expr} doesn't exist or
+		there is no such window, -1 is returned.  Example: >
+
+	echo "A window containing buffer 1 is " . (bufwinid(1))
+<
+		Only deals with the current tab page.
+
 bufwinnr({expr})					*bufwinnr()*
 		The result is a Number, which is the number of the first
 		window associated with buffer {expr}.  For the use of {expr},
@@ -3721,6 +3733,7 @@ getcwd([{winnr}[, {tabnr}]])				*getcwd()*
 			getcwd(0)
 			getcwd(0, 0)
 <		If {winnr} is -1 it is ignored, only the tab is resolved.
+		{winnr} can be the window number or the window ID.
 
 
 getfsize({fname})					*getfsize()*
@@ -3815,7 +3828,9 @@ getline({lnum} [, {end}])
 
 getloclist({nr})					*getloclist()*
 		Returns a list with all the entries in the location list for
-		window {nr}. When {nr} is zero the current window is used.
+		window {nr}. {nr} can be the window number or the window ID.
+		When {nr} is zero the current window is used.
+
 		For a location list window, the displayed location list is
 		returned.  For an invalid window number {nr}, an empty list is
 		returned. Otherwise, same as |getqflist()|.
@@ -3943,6 +3958,7 @@ gettabwinvar({tabnr}, {winnr}, {varname} [, {def}])		*gettabwinvar()*
 		Note that {varname} must be the name without "w:".
 		Tabs are numbered starting with one.  For the current tabpage
 		use |getwinvar()|.
+		{winnr} can be the window number or the window ID.
 		When {winnr} is zero the current window is used.
 		This also works for a global option, buffer-local option and
 		window-local option, but it doesn't work for a global variable
@@ -4070,7 +4086,8 @@ haslocaldir([{winnr}[, {tabnr}]])			*haslocaldir()*
 			haslocaldir()
 			haslocaldir(0)
 			haslocaldir(0, 0)
-<		If {winnr} is -1 it is ignored, only the tab is resolved.
+<		{winnr} can be the window number or the window ID.
+		If {winnr} is -1 it is ignored, only the tab is resolved.
 
 hasmapto({what} [, {mode} [, {abbr}]])			*hasmapto()*
 		The result is a Number, which is 1 if there is a mapping that
@@ -6059,11 +6076,13 @@ setline({lnum}, {text})					*setline()*
 
 setloclist({nr}, {list} [, {action}[, {title}]])	*setloclist()*
 		Create or replace or add to the location list for window {nr}.
-		When {nr} is zero the current window is used. For a location
-		list window, the displayed location list is modified.  For an
-		invalid window number {nr}, -1 is returned. If {title} is
-		given, it will be used to set |w:quickfix_title| after opening
-		the location window.
+		{nr} can be the window number or the window ID.
+		When {nr} is zero the current window is used.
+
+		For a location list window, the displayed location list is
+		modified.  For an invalid window number {nr}, -1 is returned. If
+		{title} is given, it will be used to set |w:quickfix_title|
+		after opening the location window.
 		Otherwise, same as |setqflist()|.
 		Also see |location-list|.
 
@@ -6227,6 +6246,7 @@ settabwinvar({tabnr}, {winnr}, {varname}, {val})	*settabwinvar()*
 		{val}.
 		Tabs are numbered starting with one.  For the current tabpage
 		use |setwinvar()|.
+		{winnr} can be the window number or the window ID.
 		When {winnr} is zero the current window is used.
 		This also works for a global or local buffer option, but it
 		doesn't work for a global or local buffer variable.
@@ -7255,9 +7275,11 @@ win_id2win({expr})					*win_id2win()*
 
 							*winbufnr()*
 winbufnr({nr})	The result is a Number, which is the number of the buffer
-		associated with window {nr}.  When {nr} is zero, the number of
-		the buffer in the current window is returned.  When window
-		{nr} doesn't exist, -1 is returned.
+		associated with window {nr}.  {nr} can be the window number or
+		the window ID.
+		When {nr} is zero, the number of the buffer in the current
+		window is returned.
+		When window {nr} doesn't exist, -1 is returned.
 		Example: >
   :echo "The file in the current window is " . bufname(winbufnr(0))
 <
@@ -7268,6 +7290,7 @@ wincol()	The result is a Number, which is the virtual column of the
 
 winheight({nr})						*winheight()*
 		The result is a Number, which is the height of window {nr}.
+		{nr} can be the window number or the window ID.
 		When {nr} is zero, the height of the current window is
 		returned.  When window {nr} doesn't exist, -1 is returned.
 		An existing window always has a height of zero or more.
@@ -7347,6 +7370,7 @@ winsaveview()	Returns a |Dictionary| that contains information to restore
 
 winwidth({nr})						*winwidth()*
 		The result is a Number, which is the width of window {nr}.
+		{nr} can be the window number or the window ID.
 		When {nr} is zero, the width of the current window is
 		returned.  When window {nr} doesn't exist, -1 is returned.
 		An existing window always has a width of zero or more.
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index 4aba1ec1bb..cae032f437 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -6709,7 +6709,6 @@ static int get_env_tv(char_u **arg, typval_T *rettv, int evaluate)
 # include "funcs.generated.h"
 #endif
 
-
 /*
  * Function given to ExpandGeneric() to obtain the list of internal
  * or user defined function names.
@@ -7712,26 +7711,47 @@ static void f_bufnr(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     rettv->vval.v_number = -1;
 }
 
-/*
- * "bufwinnr(nr)" function
- */
-static void f_bufwinnr(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+static void buf_win_common(typval_T *argvars, typval_T *rettv, bool get_nr)
 {
-  (void)get_tv_number(&argvars[0]);         /* issue errmsg if type error */
-  ++emsg_off;
+  int error = false;
+  (void)get_tv_number_chk(&argvars[0], &error);  // issue errmsg if type error
+  if (error) {  // the argument has an invalid type
+    rettv->vval.v_number = -1;
+    return;
+  }
+
+  emsg_off++;
+  buf_T *buf = get_buf_tv(&argvars[0], true);
+  if (buf == NULL) {  // no need to search if buffer was not found
+    rettv->vval.v_number = -1;
+    goto end;
+  }
 
-  buf_T *buf = get_buf_tv(&argvars[0], TRUE);
   int winnr = 0;
+  int winid;
   bool found_buf = false;
   FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
-    ++winnr;
+    winnr++;
     if (wp->w_buffer == buf) {
       found_buf = true;
+      winid = wp->handle;
       break;
     }
   }
-  rettv->vval.v_number = (found_buf ? winnr : -1);
-  --emsg_off;
+  rettv->vval.v_number = (found_buf ? (get_nr ? winnr : winid) : -1);
+end:
+  emsg_off--;
+}
+
+/// "bufwinid(nr)" function
+static void f_bufwinid(typval_T *argvars, typval_T *rettv, FunPtr fptr) {
+  buf_win_common(argvars, rettv, false);
+}
+
+/// "bufwinnr(nr)" function
+static void f_bufwinnr(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+{
+  buf_win_common(argvars, rettv, true);
 }
 
 /*
@@ -10279,7 +10299,11 @@ find_win_by_nr (
   }
 
   FOR_ALL_WINDOWS_IN_TAB(wp, tp) {
-    if (--nr <= 0) {
+    if (nr >= LOWEST_WIN_ID) {
+      if (wp->handle == nr) {
+        return wp;
+      }
+    } else if (--nr <= 0) {
       return wp;
     }
   }
diff --git a/src/nvim/eval.lua b/src/nvim/eval.lua
index 984ccebbf8..eaaee81533 100644
--- a/src/nvim/eval.lua
+++ b/src/nvim/eval.lua
@@ -45,6 +45,7 @@ return {
     bufloaded={args=1},
     bufname={args=1},
     bufnr={args={1, 2}},
+    bufwinid={args=1},
     bufwinnr={args=1},
     byte2line={args=1},
     byteidx={args=2},
diff --git a/src/nvim/testdir/test_window_id.vim b/src/nvim/testdir/test_window_id.vim
index fa3ebd757e..66656e1d0a 100644
--- a/src/nvim/testdir/test_window_id.vim
+++ b/src/nvim/testdir/test_window_id.vim
@@ -3,17 +3,22 @@
 func Test_win_getid()
   edit one
   let id1 = win_getid()
+  let w:one = 'one'
   split two
   let id2 = win_getid()
   let bufnr2 = bufnr('%')
+  let w:two = 'two'
   split three
   let id3 = win_getid()
+  let w:three = 'three'
   tabnew
   edit four
   let id4 = win_getid()
+  let w:four = 'four'
   split five
   let id5 = win_getid()
   let bufnr5 = bufnr('%')
+  let w:five = 'five'
   tabnext
 
   wincmd w
@@ -28,6 +33,9 @@ func Test_win_getid()
   call assert_equal("three", expand("%"))
   call assert_equal(id3, win_getid())
   let nr3 = winnr()
+  call assert_equal('one', getwinvar(id1, 'one'))
+  call assert_equal('two', getwinvar(id2, 'two'))
+  call assert_equal('three', getwinvar(id3, 'three'))
   tabnext
   call assert_equal("five", expand("%"))
   call assert_equal(id5, win_getid())
@@ -36,7 +44,14 @@ func Test_win_getid()
   call assert_equal("four", expand("%"))
   call assert_equal(id4, win_getid())
   let nr4 = winnr()
+  call assert_equal('four', getwinvar(id4, 'four'))
+  call assert_equal('five', getwinvar(id5, 'five'))
+  call settabwinvar(1, id2, 'two', '2')
+  call setwinvar(id4, 'four', '4')
   tabnext
+  call assert_equal('4', gettabwinvar(2, id4, 'four'))
+  call assert_equal('five', gettabwinvar(2, id5, 'five'))
+  call assert_equal('2', getwinvar(id2, 'two'))
 
   exe nr1 . "wincmd w"
   call assert_equal(id1, win_getid())
diff --git a/src/nvim/version.c b/src/nvim/version.c
index f87064b408..e6ef600f8c 100644
--- a/src/nvim/version.c
+++ b/src/nvim/version.c
@@ -546,9 +546,9 @@ static int included_patches[] = {
   1898,
   // 1897,
   1896,
-  // 1895,
+  1895,
   // 1894 NA
-  // 1893,
+  1893,
   // 1892 NA
   // 1891 NA
   // 1890 NA
diff --git a/src/nvim/vim.h b/src/nvim/vim.h
index 09e9e850a7..6bbd9b58ef 100644
--- a/src/nvim/vim.h
+++ b/src/nvim/vim.h
@@ -316,4 +316,7 @@ enum {
 #define DIP_OPT 0x10    // also use "opt" directory in 'packpath'
 #define DIP_NORTP 0x20  // do not use 'runtimepath'
 
+// Lowest number used for window ID. Cannot have this many windows per tab.
+#define LOWEST_WIN_ID 1000
+
 #endif /* NVIM_VIM_H */
diff --git a/src/nvim/window.c b/src/nvim/window.c
index 0be586c606..a259654d52 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -3694,7 +3694,7 @@ win_T *buf_jump_open_tab(buf_T *buf)
  */
 static win_T *win_alloc(win_T *after, int hidden)
 {
-  static int last_win_id = 0;
+  static int last_win_id = LOWEST_WIN_ID - 1;
 
   // allocate window structure and linesizes arrays
   win_T *new_wp = xcalloc(1, sizeof(win_T));
diff --git a/test/functional/api/server_requests_spec.lua b/test/functional/api/server_requests_spec.lua
index 480f099b4d..3245e1b52d 100644
--- a/test/functional/api/server_requests_spec.lua
+++ b/test/functional/api/server_requests_spec.lua
@@ -164,7 +164,8 @@ describe('server -> client', function()
 
     it('can communicate buffers, tabpages, and windows', function()
       eq({1}, eval("rpcrequest(vim, 'nvim_list_tabpages')"))
-      eq({1}, eval("rpcrequest(vim, 'nvim_list_wins')"))
+      -- Window IDs start at 1000 (LOWEST_WIN_ID in vim.h)
+      eq({1000}, eval("rpcrequest(vim, 'nvim_list_wins')"))
 
       local buf = eval("rpcrequest(vim, 'nvim_list_bufs')")[1]
       eq(1, buf)