diff --git a/components/script/dom/bindings/codegen/BindingGen.py b/components/script/dom/bindings/codegen/BindingGen.py
index 0649db6f1f9..5debf3e1f0f 100644
--- a/components/script/dom/bindings/codegen/BindingGen.py
+++ b/components/script/dom/bindings/codegen/BindingGen.py
@@ -3,9 +3,9 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 import sys
-sys.path.append("./parser/")
-sys.path.append("./ply/")
 import os
+sys.path.append(os.path.join(".", "parser"))
+sys.path.append(os.path.join(".", "ply"))
 import cPickle
 from Configuration import Configuration
 from CodegenRust import CGBindingRoot, replaceFileIfChanged
diff --git a/components/script/dom/bindings/codegen/GlobalGen.py b/components/script/dom/bindings/codegen/GlobalGen.py
index 4d564aab0ac..6a83d069e02 100644
--- a/components/script/dom/bindings/codegen/GlobalGen.py
+++ b/components/script/dom/bindings/codegen/GlobalGen.py
@@ -6,9 +6,9 @@
 # and generate information for subsequent phases.
 
 import sys
-sys.path.append("./parser/")
-sys.path.append("./ply/")
 import os
+sys.path.append(os.path.join(".", "parser"))
+sys.path.append(os.path.join(".", "ply"))
 import WebIDL
 import cPickle
 from Configuration import Configuration
@@ -66,7 +66,7 @@ def main():
         ('RegisterBindings', 'RegisterBindings.rs'),
         ('InterfaceTypes', 'InterfaceTypes.rs'),
         ('InheritTypes', 'InheritTypes.rs'),
-        ('Bindings', 'Bindings/mod.rs'),
+        ('Bindings', os.path.join('Bindings', 'mod.rs')),
         ('UnionTypes', 'UnionTypes.rs'),
     ]
 
diff --git a/python/mach_bootstrap.py b/python/mach_bootstrap.py
index 2e36b0cefc0..19b1ad666e8 100644
--- a/python/mach_bootstrap.py
+++ b/python/mach_bootstrap.py
@@ -11,18 +11,18 @@ import sys
 from distutils.spawn import find_executable
 
 SEARCH_PATHS = [
-    "python/mach",
-    "tests/wpt",
-    "tests/wpt/harness",
+    os.path.join("python", "mach"),
+    os.path.join("tests", "wpt"),
+    os.path.join("tests", "wpt", "harness"),
 ]
 
 # Individual files providing mach commands.
 MACH_MODULES = [
-    'python/servo/bootstrap_commands.py',
-    'python/servo/build_commands.py',
-    'python/servo/testing_commands.py',
-    'python/servo/post_build_commands.py',
-    'python/servo/devenv_commands.py',
+    os.path.join('python', 'servo', 'bootstrap_commands.py'),
+    os.path.join('python', 'servo', 'build_commands.py'),
+    os.path.join('python', 'servo', 'testing_commands.py'),
+    os.path.join('python', 'servo', 'post_build_commands.py'),
+    os.path.join('python', 'servo', 'devenv_commands.py'),
 ]
 
 
diff --git a/python/tidy.py b/python/tidy.py
index 95691893525..b2e94fcafca 100644
--- a/python/tidy.py
+++ b/python/tidy.py
@@ -22,23 +22,23 @@ reftest_filetype = ".list"
 
 ignored_files = [
     # Upstream
-    "./support/*",
-    "./tests/wpt/*",
-    "./python/mach/*",
-    "./components/script/dom/bindings/codegen/parser/*",
-    "./components/script/dom/bindings/codegen/ply/*",
-    "./python/_virtualenv/*",
+    os.path.join(".", "support", "*"),
+    os.path.join(".", "tests", "wpt", "*"),
+    os.path.join(".", "python", "mach", "*"),
+    os.path.join(".", "components", "script", "dom", "bindings", "codegen", "parser", "*"),
+    os.path.join(".", "components", "script", "dom", "bindings", "codegen", "ply", "*"),
+    os.path.join(".", "python", "_virtualenv", "*"),
 
     # Generated and upstream code combined with our own. Could use cleanup
-    "./target/*",
-    "./ports/gonk/src/native_window_glue.cpp",
-    "./ports/cef/*",
+    os.path.join(".", "target", "*"),
+    os.path.join(".", "ports", "gonk", "src", "native_window_glue.cpp"),
+    os.path.join(".", "ports", "cef", "*"),
 
     # MIT license
-    "./components/util/deque/mod.rs",
+    os.path.join(".", "components", "util", "deque", "mod.rs"),
 
     # Hidden files/directories
-    "./.*",
+    os.path.join(".", ".*"),
 ]
 
 
@@ -192,8 +192,8 @@ def check_toml(file_name, contents):
 def check_rust(file_name, contents):
     if not file_name.endswith(".rs") or \
        file_name.endswith("properties.mako.rs") or \
-       file_name.endswith("style/build.rs") or \
-       file_name.endswith("unit/style/stylesheets.rs"):
+       file_name.endswith(os.path.join("style", "build.rs")) or \
+       file_name.endswith(os.path.join("unit", "style", "stylesheets.rs")):
         raise StopIteration
     contents = contents.splitlines(True)
     comment_depth = 0