diff --git a/dlls/api-ms-win-core-path-l1-1-0/api-ms-win-core-path-l1-1-0.spec b/dlls/api-ms-win-core-path-l1-1-0/api-ms-win-core-path-l1-1-0.spec
index cb10d89773c..287c5d61d96 100644
--- a/dlls/api-ms-win-core-path-l1-1-0/api-ms-win-core-path-l1-1-0.spec
+++ b/dlls/api-ms-win-core-path-l1-1-0/api-ms-win-core-path-l1-1-0.spec
@@ -1,7 +1,7 @@
 @ stub PathAllocCanonicalize
 @ stub PathAllocCombine
-@ stub PathCchAddBackslash
-@ stub PathCchAddBackslashEx
+@ stdcall PathCchAddBackslash(wstr long) kernelbase.PathCchAddBackslash
+@ stdcall PathCchAddBackslashEx(wstr long ptr ptr) kernelbase.PathCchAddBackslashEx
 @ stub PathCchAddExtension
 @ stub PathCchAppend
 @ stub PathCchAppendEx
diff --git a/dlls/kernelbase/Makefile.in b/dlls/kernelbase/Makefile.in
index 74df98ce2d5..a7db45e4c1d 100644
--- a/dlls/kernelbase/Makefile.in
+++ b/dlls/kernelbase/Makefile.in
@@ -1,4 +1,5 @@
 MODULE = kernelbase.dll
 
 C_SRCS = \
-	main.c
+	main.c \
+	path.c
diff --git a/dlls/kernelbase/kernelbase.spec b/dlls/kernelbase/kernelbase.spec
index aa67372cf5c..eafe5ab9dda 100644
--- a/dlls/kernelbase/kernelbase.spec
+++ b/dlls/kernelbase/kernelbase.spec
@@ -1029,8 +1029,8 @@
 @ stdcall PathAppendW(wstr wstr) shlwapi.PathAppendW
 @ stdcall PathCanonicalizeA(ptr str) shlwapi.PathCanonicalizeA
 @ stdcall PathCanonicalizeW(ptr wstr) shlwapi.PathCanonicalizeW
-# @ stub PathCchAddBackslash
-# @ stub PathCchAddBackslashEx
+@ stdcall PathCchAddBackslash(wstr long)
+@ stdcall PathCchAddBackslashEx(wstr long ptr ptr)
 # @ stub PathCchAddExtension
 # @ stub PathCchAppend
 # @ stub PathCchAppendEx
diff --git a/dlls/kernelbase/path.c b/dlls/kernelbase/path.c
new file mode 100644
index 00000000000..373c34e9795
--- /dev/null
+++ b/dlls/kernelbase/path.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright 2018 Nikolay Sivov
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#include <stdarg.h>
+
+#include "windef.h"
+#include "winbase.h"
+#include "pathcch.h"
+#include "strsafe.h"
+
+#include "wine/debug.h"
+#include "wine/unicode.h"
+
+WINE_DEFAULT_DEBUG_CHANNEL(path);
+
+HRESULT WINAPI PathCchAddBackslash(WCHAR *path, SIZE_T size)
+{
+    return PathCchAddBackslashEx(path, size, NULL, NULL);
+}
+
+HRESULT WINAPI PathCchAddBackslashEx(WCHAR *path, SIZE_T size, WCHAR **endptr, SIZE_T *remaining)
+{
+    BOOL needs_termination;
+    SIZE_T length;
+
+    TRACE("%s, %lu, %p, %p\n", debugstr_w(path), size, endptr, remaining);
+
+    length = strlenW(path);
+    needs_termination = size && length && path[length - 1] != '\\';
+
+    if (length >= (needs_termination ? size - 1 : size))
+    {
+        if (endptr) *endptr = NULL;
+        if (remaining) *remaining = 0;
+        return STRSAFE_E_INSUFFICIENT_BUFFER;
+    }
+
+    if (!needs_termination)
+    {
+        if (endptr) *endptr = path + length;
+        if (remaining) *remaining = size - length;
+        return S_FALSE;
+    }
+
+    path[length++] = '\\';
+    path[length] = 0;
+
+    if (endptr) *endptr = path + length;
+    if (remaining) *remaining = size - length;
+
+    return S_OK;
+}
diff --git a/dlls/kernelbase/tests/path.c b/dlls/kernelbase/tests/path.c
index fbe1d3be2f5..47c77b8c341 100644
--- a/dlls/kernelbase/tests/path.c
+++ b/dlls/kernelbase/tests/path.c
@@ -29,6 +29,8 @@
 
 #include "wine/test.h"
 
+HRESULT (WINAPI *pPathCchAddBackslash)(WCHAR *out, SIZE_T size);
+HRESULT (WINAPI *pPathCchAddBackslashEx)(WCHAR *out, SIZE_T size, WCHAR **endptr, SIZE_T *remaining);
 HRESULT (WINAPI *pPathCchCombineEx)(WCHAR *out, SIZE_T size, const WCHAR *path1, const WCHAR *path2, DWORD flags);
 
 static const struct
@@ -113,11 +115,145 @@ static void test_PathCchCombineEx(void)
     }
 }
 
+struct addbackslash_test
+{
+    const char *path;
+    const char *result;
+    HRESULT hr;
+    SIZE_T size;
+    SIZE_T remaining;
+};
+
+static const struct addbackslash_test addbackslash_tests[] =
+{
+    { "C:",    "C:\\",    S_OK, MAX_PATH, MAX_PATH - 3 },
+    { "a.txt", "a.txt\\", S_OK, MAX_PATH, MAX_PATH - 6 },
+    { "a/b",   "a/b\\",   S_OK, MAX_PATH, MAX_PATH - 4 },
+
+    { "C:\\",  "C:\\",    S_FALSE, MAX_PATH, MAX_PATH - 3 },
+    { "C:\\",  "C:\\",    S_FALSE, 4, 1 },
+
+    { "C:",    "C:",      STRSAFE_E_INSUFFICIENT_BUFFER, 2, 0 },
+    { "C:",    "C:",      STRSAFE_E_INSUFFICIENT_BUFFER, 3, 1 },
+    { "C:\\",  "C:\\",    STRSAFE_E_INSUFFICIENT_BUFFER, 2, 0 },
+    { "C:\\",  "C:\\",    STRSAFE_E_INSUFFICIENT_BUFFER, 3, 0 },
+    { "C:\\",  "C:\\",    STRSAFE_E_INSUFFICIENT_BUFFER, 0, 0 },
+    { "C:",    "C:",      STRSAFE_E_INSUFFICIENT_BUFFER, 0, 0 },
+};
+
+static void test_PathCchAddBackslash(void)
+{
+    WCHAR pathW[MAX_PATH];
+    unsigned int i;
+    HRESULT hr;
+
+    if (!pPathCchAddBackslash)
+    {
+        win_skip("PathCchAddBackslash() is not availale.\n");
+        return;
+    }
+
+    pathW[0] = 0;
+    hr = pPathCchAddBackslash(pathW, 0);
+    ok(hr == STRSAFE_E_INSUFFICIENT_BUFFER, "Unexpected hr %#x.\n", hr);
+    ok(pathW[0] == 0, "Unexpected path.\n");
+
+    pathW[0] = 0;
+    hr = pPathCchAddBackslash(pathW, 1);
+    ok(hr == S_FALSE, "Unexpected hr %#x.\n", hr);
+    ok(pathW[0] == 0, "Unexpected path.\n");
+
+    pathW[0] = 0;
+    hr = pPathCchAddBackslash(pathW, 2);
+    ok(hr == S_FALSE, "Unexpected hr %#x.\n", hr);
+    ok(pathW[0] == 0, "Unexpected path.\n");
+
+    for (i = 0; i < sizeof(addbackslash_tests)/sizeof(addbackslash_tests[0]); i++)
+    {
+        const struct addbackslash_test *test = &addbackslash_tests[i];
+        char path[MAX_PATH];
+
+        MultiByteToWideChar(CP_ACP, 0, test->path, -1, pathW, sizeof(pathW)/sizeof(pathW[0]));
+        hr = pPathCchAddBackslash(pathW, test->size);
+        ok(hr == test->hr, "%u: unexpected return value %#x.\n", i, hr);
+
+        WideCharToMultiByte(CP_ACP, 0, pathW, -1, path, sizeof(path)/sizeof(path[0]), NULL, NULL);
+        ok(!strcmp(path, test->result), "%u: unexpected resulting path %s.\n", i, path);
+    }
+}
+
+static void test_PathCchAddBackslashEx(void)
+{
+    WCHAR pathW[MAX_PATH];
+    SIZE_T remaining;
+    unsigned int i;
+    HRESULT hr;
+    WCHAR *ptrW;
+
+    if (!pPathCchAddBackslashEx)
+    {
+        win_skip("PathCchAddBackslashEx() is not availale.\n");
+        return;
+    }
+
+    pathW[0] = 0;
+    hr = pPathCchAddBackslashEx(pathW, 0, NULL, NULL);
+    ok(hr == STRSAFE_E_INSUFFICIENT_BUFFER, "Unexpected hr %#x.\n", hr);
+    ok(pathW[0] == 0, "Unexpected path.\n");
+
+    pathW[0] = 0;
+    ptrW = (void *)0xdeadbeef;
+    remaining = 123;
+    hr = pPathCchAddBackslashEx(pathW, 1, &ptrW, &remaining);
+    ok(hr == S_FALSE, "Unexpected hr %#x.\n", hr);
+    ok(pathW[0] == 0, "Unexpected path.\n");
+    ok(ptrW == pathW, "Unexpected endptr %p.\n", ptrW);
+    ok(remaining == 1, "Unexpected remaining size.\n");
+
+    pathW[0] = 0;
+    hr = pPathCchAddBackslashEx(pathW, 2, NULL, NULL);
+    ok(hr == S_FALSE, "Unexpected hr %#x.\n", hr);
+    ok(pathW[0] == 0, "Unexpected path.\n");
+
+    for (i = 0; i < sizeof(addbackslash_tests)/sizeof(addbackslash_tests[0]); i++)
+    {
+        const struct addbackslash_test *test = &addbackslash_tests[i];
+        char path[MAX_PATH];
+
+        MultiByteToWideChar(CP_ACP, 0, test->path, -1, pathW, sizeof(pathW)/sizeof(pathW[0]));
+        hr = pPathCchAddBackslashEx(pathW, test->size, NULL, NULL);
+        ok(hr == test->hr, "%u: unexpected return value %#x.\n", i, hr);
+
+        WideCharToMultiByte(CP_ACP, 0, pathW, -1, path, sizeof(path)/sizeof(path[0]), NULL, NULL);
+        ok(!strcmp(path, test->result), "%u: unexpected resulting path %s.\n", i, path);
+
+        ptrW = (void *)0xdeadbeef;
+        remaining = 123;
+        MultiByteToWideChar(CP_ACP, 0, test->path, -1, pathW, sizeof(pathW)/sizeof(pathW[0]));
+        hr = pPathCchAddBackslashEx(pathW, test->size, &ptrW, &remaining);
+        ok(hr == test->hr, "%u: unexpected return value %#x.\n", i, hr);
+        if (SUCCEEDED(hr))
+        {
+            ok(ptrW == (pathW + lstrlenW(pathW)), "%u: unexpected end pointer.\n", i);
+            ok(remaining == test->remaining, "%u: unexpected remaining buffer length.\n", i);
+        }
+        else
+        {
+            ok(ptrW == NULL, "%u: unexpecred end pointer.\n", i);
+            ok(remaining == 0, "%u: unexpected remaining buffer length.\n", i);
+        }
+    }
+}
+
 START_TEST(path)
 {
     HMODULE hmod = LoadLibraryA("kernelbase.dll");
 
     pPathCchCombineEx = (void *)GetProcAddress(hmod, "PathCchCombineEx");
+    pPathCchAddBackslash = (void *)GetProcAddress(hmod, "PathCchAddBackslash");
+    pPathCchAddBackslashEx = (void *)GetProcAddress(hmod, "PathCchAddBackslashEx");
 
     test_PathCchCombineEx();
+    test_PathCchAddBackslash();
+    test_PathCchAddBackslashEx();
 }
diff --git a/include/pathcch.h b/include/pathcch.h
index 8831c5238d2..2b2aed4c8f9 100644
--- a/include/pathcch.h
+++ b/include/pathcch.h
@@ -23,4 +23,6 @@
 #define PATHCCH_DO_NOT_NORMALIZE_SEGMENTS       0x08
 #define PATHCCH_ENSURE_IS_EXTENDED_LENGTH_PATH  0x10
 
+HRESULT WINAPI PathCchAddBackslash(WCHAR *path, SIZE_T size);
+HRESULT WINAPI PathCchAddBackslashEx(WCHAR *path, SIZE_T size, WCHAR **end, SIZE_T *remaining);
 HRESULT WINAPI PathCchCombineEx(WCHAR *out, SIZE_T size, const WCHAR *path1, const WCHAR *path2, DWORD flags);
diff --git a/tools/make_specfiles b/tools/make_specfiles
index 1e8a894277e..e9bc1f4d8d7 100755
--- a/tools/make_specfiles
+++ b/tools/make_specfiles
@@ -303,6 +303,7 @@ my @dll_groups =
  [
   "kernelbase",
   "api-ms-win-appmodel-runtime-l1-1-2",
+  "api-ms-win-core-path-l1-1-0",
   "api-ms-win-core-quirks-l1-1-0",
   "api-ms-win-security-grouppolicy-l1-1-0",
  ],