diff --git a/nvchecker/source/aiohttp_httpclient.py b/nvchecker/source/aiohttp_httpclient.py
index 4fd8b4f..bc73107 100644
--- a/nvchecker/source/aiohttp_httpclient.py
+++ b/nvchecker/source/aiohttp_httpclient.py
@@ -4,6 +4,8 @@
 import atexit
 import asyncio
 import aiohttp
+from .httpclient import DEFAULT_USER_AGENT
+
 connector = aiohttp.TCPConnector(limit=20)
 
 __all__ = ['session', 'HTTPError', 'NetworkErrors']
@@ -19,6 +21,8 @@ class BetterClientSession(aiohttp.ClientSession):
         if hasattr(self, "nv_config") and self.nv_config.get("proxy"):
             kwargs.setdefault("proxy", self.nv_config.get("proxy"))
 
+        kwargs.setdefault("headers", {}).setdefault('User-Agent', DEFAULT_USER_AGENT)
+
         res = await super(BetterClientSession, self)._request(
             *args, **kwargs)
         if res.status >= 400:
diff --git a/nvchecker/source/github.py b/nvchecker/source/github.py
index 6ecd499..e19b804 100644
--- a/nvchecker/source/github.py
+++ b/nvchecker/source/github.py
@@ -46,7 +46,6 @@ async def get_version_real(name, conf, **kwargs):
     url += '?' + urlencode(parameters)
   headers = {
     'Accept': 'application/vnd.github.quicksilver-preview+json',
-    'User-Agent': 'lilydjwg/nvchecker',
   }
   if 'NVCHECKER_GITHUB_TOKEN' in os.environ:
     headers['Authorization'] = 'token %s' % os.environ['NVCHECKER_GITHUB_TOKEN']
diff --git a/nvchecker/source/httpclient.py b/nvchecker/source/httpclient.py
new file mode 100644
index 0000000..a1666e1
--- /dev/null
+++ b/nvchecker/source/httpclient.py
@@ -0,0 +1 @@
+DEFAULT_USER_AGENT = 'lilydjwg/nvchecker'
diff --git a/nvchecker/source/tornado_httpclient.py b/nvchecker/source/tornado_httpclient.py
index dcf4ae8..74ab246 100644
--- a/nvchecker/source/tornado_httpclient.py
+++ b/nvchecker/source/tornado_httpclient.py
@@ -15,6 +15,8 @@ try:
 except ImportError:
   pycurl = None
 
+from .httpclient import DEFAULT_USER_AGENT
+
 __all__ = ['session', 'HTTPError', 'NetworkErrors']
 
 client = AsyncHTTPClient()
@@ -51,6 +53,7 @@ class Session:
       q = urlencode(params)
       url += '?' + q
 
+    kwargs.setdefault("headers", {}).setdefault('User-Agent', DEFAULT_USER_AGENT)
     r = HTTPRequest(url, **kwargs)
     return ResponseManager(r)