diff --git a/cpplint/cpplint.py b/cpplint/cpplint.py
index 7c624f2ad..a9815124f 100755
--- a/cpplint/cpplint.py
+++ b/cpplint/cpplint.py
@@ -114,12 +114,13 @@
       ignored.
 
       Examples:
-        Assuming that src/.git exists, the header guard CPP variables for
-        src/chrome/browser/ui/browser.h are:
+        Assuming that top/src/.git exists (and cwd=top/src), the header guard
+        CPP variables for top/src/chrome/browser/ui/browser.h are:
 
         No flag => CHROME_BROWSER_UI_BROWSER_H_
         --root=chrome => BROWSER_UI_BROWSER_H_
         --root=chrome/browser => UI_BROWSER_H_
+        --root=.. => SRC_CHROME_BROWSER_UI_BROWSER_H_
 
     linelength=digits
       This is the allowed line length for the project. The default value is
@@ -168,9 +169,9 @@
     "linelength" allows to specify the allowed line length for the project.
 
     The "root" option is similar in function to the --root flag (see example
-    above).
-    
-    The "headers" option is similar in function to the --headers flag 
+    above). Paths are relative to the directory of the CPPLINT.cfg.
+
+    The "headers" option is similar in function to the --headers flag
     (see example above).
 
     CPPLINT.cfg has an effect on files in the same directory and all
@@ -539,6 +540,7 @@
 # The root directory used for deriving header guard CPP variable.
 # This is set by --root flag.
 _root = None
+_root_debug = False
 
 # The allowed line length of files.
 # This is set by --linelength flag.
@@ -1802,8 +1804,14 @@ def GetHeaderGuardCPPVariable(filename):
   file_path_from_root = fileinfo.RepositoryName()
 
   def FixupPathFromRoot():
+    if _root_debug:
+      sys.stderr.write("\n_root fixup, _root = '%s', repository name = '%s'\n"
+          %(_root, fileinfo.RepositoryName()))
+
     # Process the file path with the --root flag if it was set.
     if not _root:
+      if _root_debug:
+        sys.stderr.write("_root unspecified\n")
       return file_path_from_root
 
     def StripListPrefix(lst, prefix):
@@ -1817,6 +1825,11 @@ def StripListPrefix(lst, prefix):
     #   --root=subdir , lstrips subdir from the header guard
     maybe_path = StripListPrefix(PathSplitToList(file_path_from_root),
                                  PathSplitToList(_root))
+
+    if _root_debug:
+      sys.stderr.write("_root lstrip (maybe_path=%s, file_path_from_root=%s," +
+          " _root=%s)\n" %(maybe_path, file_path_from_root, _root))
+
     if maybe_path:
       return os.path.join(*maybe_path)
 
@@ -1826,9 +1839,17 @@ def StripListPrefix(lst, prefix):
 
     maybe_path = StripListPrefix(PathSplitToList(full_path),
                                  PathSplitToList(root_abspath))
+
+    if _root_debug:
+      sys.stderr.write("_root prepend (maybe_path=%s, full_path=%s, " +
+          "root_abspath=%s)\n" %(maybe_path, full_path, root_abspath))
+
     if maybe_path:
       return os.path.join(*maybe_path)
 
+    if _root_debug:
+      sys.stderr.write("_root ignore, returning %s\n" %(file_path_from_root))
+
     #   --root=FAKE_DIR is ignored
     return file_path_from_root
 
@@ -5947,7 +5968,8 @@ def ProcessConfigOverrides(filename):
                 sys.stderr.write('Line length must be numeric.')
           elif name == 'root':
             global _root
-            _root = val
+            # root directories are specified relative to CPPLINT.cfg dir.
+            _root = os.path.join(os.path.dirname(cfg_file), val)
           elif name == 'headers':
             ProcessHppHeadersOption(val)
           else:
diff --git a/cpplint/cpplint_unittest.py b/cpplint/cpplint_unittest.py
index 30f640e23..a1cd48166 100755
--- a/cpplint/cpplint_unittest.py
+++ b/cpplint/cpplint_unittest.py
@@ -4218,6 +4218,8 @@ def testBuildHeaderGuard(self):
           error_collector.ResultList())
 
   def testBuildHeaderGuardWithRoot(self):
+    # note: Tested file paths must be real, otherwise
+    # the repository name lookup will fail.
     file_path = os.path.join(os.path.dirname(os.path.abspath(__file__)),
                              'cpplint_test_header.h')
     file_info = cpplint.FileInfo(file_path)
@@ -4238,9 +4240,33 @@ def testBuildHeaderGuardWithRoot(self):
     #
 
     # left-strip the header guard by using a root dir inside of the repo dir.
+    # relative directory
     cpplint._root = 'cpplint'
     self.assertEquals('CPPLINT_TEST_HEADER_H_',
                       cpplint.GetHeaderGuardCPPVariable(file_path))
+
+    nested_file_path = os.path.join(os.path.dirname(os.path.abspath(__file__)),
+                                    os.path.join('nested',
+                                                 'cpplint_test_header.h'))
+    cpplint._root = os.path.join('cpplint', 'nested')
+    actual = cpplint.GetHeaderGuardCPPVariable(nested_file_path)
+    self.assertEquals('CPPLINT_TEST_HEADER_H_',
+                      actual)
+
+    # absolute directory
+    # (note that CPPLINT.cfg root=setting is always made absolute)
+    cpplint._root = os.path.join(os.path.dirname(os.path.abspath(__file__)))
+    self.assertEquals('CPPLINT_TEST_HEADER_H_',
+                      cpplint.GetHeaderGuardCPPVariable(file_path))
+
+    nested_file_path = os.path.join(os.path.dirname(os.path.abspath(__file__)),
+                                    os.path.join('nested',
+                                                 'cpplint_test_header.h'))
+    cpplint._root = os.path.join(os.path.dirname(os.path.abspath(__file__)),
+                                 'nested')
+    self.assertEquals('CPPLINT_TEST_HEADER_H_',
+                      cpplint.GetHeaderGuardCPPVariable(nested_file_path))
+
     # --root flag is ignored if an non-existent directory is specified.
     cpplint._root = 'NON_EXISTENT_DIR'
     self.assertEquals('CPPLINT_CPPLINT_TEST_HEADER_H_',
@@ -4250,6 +4276,7 @@ def testBuildHeaderGuardWithRoot(self):
     # than the repo dir
 
     # (using absolute paths)
+    # (note that CPPLINT.cfg root=setting is always made absolute)
     this_files_path = os.path.dirname(os.path.abspath(__file__))
     (styleguide_path, this_files_dir) = os.path.split(this_files_path)
     (styleguide_parent_path, _) = os.path.split(styleguide_path)
@@ -4260,6 +4287,10 @@ def testBuildHeaderGuardWithRoot(self):
     self.assertEquals('STYLEGUIDE_CPPLINT_CPPLINT_TEST_HEADER_H_',
                       cpplint.GetHeaderGuardCPPVariable(file_path))
 
+    # To run the 'relative path' tests, we must be in the directory of this test file.
+    cur_dir = os.getcwd()
+    os.chdir(this_files_path)
+
     # (using relative paths)
     styleguide_rel_path = os.path.relpath(styleguide_path, this_files_path)
     # '..'
@@ -4275,6 +4306,9 @@ def testBuildHeaderGuardWithRoot(self):
 
     cpplint._root = None
 
+    # Restore previous CWD.
+    os.chdir(cur_dir)
+
   def testPathSplitToList(self):
     self.assertEquals([''],
                       cpplint.PathSplitToList(os.path.join('')))
diff --git a/cpplint/nested/cpplint_test_header.h b/cpplint/nested/cpplint_test_header.h
new file mode 100644
index 000000000..4307e8008
--- /dev/null
+++ b/cpplint/nested/cpplint_test_header.h
@@ -0,0 +1 @@
+// A test header for cpplint_unittest.py.