diff --git a/compat/mingw.c b/compat/mingw.c
index 40908883a0e81f..7529f4ed65e343 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -480,7 +480,8 @@ int mingw_chdir(const char *dirname)
 	wchar_t wdirname[MAX_PATH];
 	if (xutftowcs_canonical_path(wdirname, dirname) < 0)
 		return -1;
-	return _wchdir(wdirname);
+	/* TODO: _wchdir() does not support long paths */
+	return _wchdir(strip_abspath_prefix(wdirname));
 }
 
 int mingw_chmod(const char *filename, int mode)
@@ -696,7 +697,8 @@ char *mingw_mktemp(char *template)
 	wchar_t wtemplate[MAX_PATH];
 	if (xutftowcs_path(wtemplate, template) < 0)
 		return NULL;
-	if (!_wmktemp(wtemplate))
+	/* TODO: _wmktemp() does not support long paths. */
+	if (!_wmktemp(strip_abspath_prefix(wtemplate)))
 		return NULL;
 	if (xwcstoutf(template, wtemplate, strlen(template) + 1) < 0)
 		return NULL;
@@ -767,7 +769,7 @@ char *mingw_getcwd(char *pointer, int len)
 	wchar_t wpointer[MAX_PATH];
 	if (!_wgetcwd(wpointer, ARRAY_SIZE(wpointer)))
 		return NULL;
-	if (xwcstoutf(pointer, wpointer, len) < 0)
+	if (xwcstoutf(pointer, strip_abspath_prefix(wpointer), len) < 0)
 		return NULL;
 	for (i = 0; pointer[i]; i++)
 		if (pointer[i] == '\\')
@@ -1165,8 +1167,8 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
 	wenvblk = make_environment_block(deltaenv);
 
 	memset(&pi, 0, sizeof(pi));
-	ret = CreateProcessW(wcmd, wargs, NULL, NULL, TRUE, flags,
-		wenvblk, dir ? wdir : NULL, &si, &pi);
+	ret = CreateProcessW(strip_abspath_prefix(wcmd), wargs, NULL, NULL, TRUE, flags,
+		wenvblk, dir ? strip_abspath_prefix(wdir) : NULL, &si, &pi);
 
 	free(wenvblk);
 	free(wargs);
diff --git a/compat/mingw.h b/compat/mingw.h
index 4b3df96d619fd5..89bc7e4f0ae0c7 100644
--- a/compat/mingw.h
+++ b/compat/mingw.h
@@ -80,6 +80,13 @@ struct itimerval {
  */
 #undef HELP_COMMAND /* from winuser.h */
 
+/*
+ * redefine MAX_PATH to SHRT_MAX; the actual maximum when using
+ * long Windows paths with "\\?\"
+ */
+#undef MAX_PATH
+#define MAX_PATH SHRT_MAX
+
 /*
  * trivial stubs
  */
@@ -357,6 +364,16 @@ HANDLE winansi_get_osfhandle(int fd);
  */
 
 #define has_dos_drive_prefix(path) (isalpha(*(path)) && (path)[1] == ':')
+#define has_win_abspath_prefix(path) ((path)[0] == '\\' && (path)[1] == '\\' \
+			&& (path)[2] == '?' && (path)[3] == '\\')
+#define has_win_abspath_prefix_w(path) ((path)[0] == L'\\' && (path)[1] == L'\\' \
+			&& (path)[2] == L'?' && (path)[3] == L'\\')
+static inline wchar_t * strip_abspath_prefix(wchar_t *path)
+{
+	if (path && has_win_abspath_prefix_w(path))
+		return &path[4];
+	return path;
+}
 #define is_dir_sep(c) ((c) == '/' || (c) == '\\')
 static inline char *mingw_find_last_dir_sep(const char *path)
 {
@@ -457,18 +474,23 @@ static inline int xutftowcs_path(wchar_t *wcs, const char *utf)
  */
 static inline int xutftowcs_canonical_path(wchar_t *wcs, const char *utf)
 {
-	wchar_t tmp[SHRT_MAX];
+	wchar_t tmp[MAX_PATH];
 	int result;
-	result = xutftowcsn(tmp, utf, SHRT_MAX, -1);
+	result = xutftowcsn(tmp, utf, MAX_PATH, -1);
 	if (result < 0 && errno == ERANGE)
 		errno = ENAMETOOLONG;
 	else if (wcsncmp(tmp, L"nul", 4) == 0 )
 		wcsncpy(wcs, tmp, 4);
 	else {
-		wchar_t tmp2[SHRT_MAX];
-		GetFullPathNameW(tmp, SHRT_MAX, tmp2, NULL);
-		if (wcslen(tmp2) < MAX_PATH)
+		wchar_t tmp2[MAX_PATH];
+		GetFullPathNameW(tmp, MAX_PATH, tmp2, NULL);
+		if (wcslen(tmp2) < MAX_PATH && has_win_abspath_prefix_w(tmp2))
 			wcsncpy(wcs, tmp2, MAX_PATH - 1);
+		/* magic: 5 = \\?\ plus null */
+		else if (wcslen(tmp2) < MAX_PATH - 5 && !has_win_abspath_prefix_w(tmp2)) {
+			wcscpy(wcs, L"\\\\?\\");
+			wcsncat(wcs, tmp2, MAX_PATH - 5);
+		}
 		else {
 			result = -1;
 			errno = ENAMETOOLONG;
diff --git a/compat/win32/dirent.c b/compat/win32/dirent.c
index d3f68774c12c7e..f71a1f7ba80f93 100644
--- a/compat/win32/dirent.c
+++ b/compat/win32/dirent.c
@@ -73,9 +73,13 @@ DIR *dirent_opendir(const char *name)
 	if ((len = xutftowcs_canonical_path(pattern, name)) < 0)
 		return NULL;
 
-	/* append optional '/' and wildcard '*' */
+	/*
+	 * append optional '\' and wildcard '*'
+	 * note: when using "\\?\" as a prefix for long paths,
+	 * we cannot expect Windows to remap '/' to '\' for us.
+	 */
 	if (len && !is_dir_sep(pattern[len - 1]))
-		pattern[len++] = '/';
+		pattern[len++] = '\\';
 	pattern[len++] = '*';
 	pattern[len] = 0;
 
diff --git a/git-compat-util.h b/git-compat-util.h
index 2dfab4b7b70d28..633e6367f013f4 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -272,6 +272,10 @@ extern char *gitbasename(char *);
 #define has_dos_drive_prefix(path) 0
 #endif
 
+#ifndef has_win_abspath_prefix
+#define has_win_abspath_prefix(path) 0
+#endif
+
 #ifndef offset_1st_component
 #define offset_1st_component(path) (is_dir_sep((path)[0]))
 #endif
diff --git a/path.c b/path.c
index 7f59206f8e40db..2ffbf1edfa47cb 100644
--- a/path.c
+++ b/path.c
@@ -619,6 +619,12 @@ int normalize_path_copy_len(char *dst, const char *src, int *prefix_len)
 {
 	char *dst0;
 
+	/*
+	 * If path contains "\\?\", we can skip this while copying.
+	 * We will re-add this later if necessary.
+	 */
+	if (has_win_abspath_prefix(src))
+		src += 4;
 	if (has_dos_drive_prefix(src)) {
 		*dst++ = *src++;
 		*dst++ = *src++;