diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -69,12 +69,12 @@
 
 | Name            | Note |
 | --------------- | ---- |
-| GITHUB_TOKEN    | When set, the value is used to authenticate GitHub API requests. |
-| GITHUB_HOST     | The GitHub host to use when fetching packages. Port may be appended here. |
-| GITHUB_API_HOST | The host used when performing GitHub API requests. Use `GITHUB_API_PORT` for specifying the port. |
-| GITHUB_API_PORT | The port used when performing GitHub API requests. Defaults to `443` for secure requests. Defaults to `80` for insecure requests. See also: `GITHUB_INSECURE`. |
-| GITHUB_INSECURE | When set to anything but the empty string, requests are performed over `http` instead of `https`. |
-| GITHUB_PATH     | The base path used when performing GitHub API requests. |
+| GITHUB_TOKEN or NIV_GITHUB_TOKEN | When set, the value is used to authenticate GitHub API requests. |
+| GITHUB_HOST or NIV_GITHUB_HOST | The GitHub host to use when fetching packages. Port may be appended here. |
+| GITHUB_API_HOST or NIV_GITHUB_API_HOST | The host used when performing GitHub API requests. Use `GITHUB_API_PORT` for specifying the port. |
+| GITHUB_API_PORT or NIV_GITHUB_API_PORT | The port used when performing GitHub API requests. Defaults to `443` for secure requests. Defaults to `80` for insecure requests. See also: `GITHUB_INSECURE`. |
+| NIV_GITHUB_INSECURE | When set to anything but the empty string, requests are performed over `http` instead of `https`. |
+| NIV_GITHUB_PATH     | The base path used when performing GitHub API requests. |
 
 The next two sections cover [common use cases](#getting-started) and [full command
 description](#commands).
@@ -216,7 +216,7 @@
 ```
 niv - dependency manager for Nix projects
 
-version: 0.2.17
+version: 0.2.18
 
 Usage: niv [-s|--sources-file FILE] COMMAND
 
diff --git a/niv.cabal b/niv.cabal
--- a/niv.cabal
+++ b/niv.cabal
@@ -4,10 +4,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 4857c6cf14357571406715c9ab94a54fbc920e9ae18dd7b647b8f25186023aaa
+-- hash: f33a4bacf65fdd3b3ad1ee550d862cd5394d00eb4c7f2bf5c51890eb76124fbb
 
 name:           niv
-version:        0.2.17
+version:        0.2.18
 synopsis:       Easy dependency management for Nix projects
 description:    Easy dependency management for Nix projects.
 category:       Development
diff --git a/src/Niv/Cli.hs b/src/Niv/Cli.hs
--- a/src/Niv/Cli.hs
+++ b/src/Niv/Cli.hs
@@ -24,6 +24,7 @@
 import Data.Version (showVersion)
 import Niv.Cmd
 import Niv.Git.Cmd
+import Niv.GitHub.API (warnGitHubEnvVars)
 import Niv.GitHub.Cmd
 import Niv.Local.Cmd
 import Niv.Logger
@@ -52,6 +53,7 @@
 
 cli :: IO ()
 cli = do
+  warnGitHubEnvVars
   (fsj, nio) <-
     execParserPure' Opts.defaultPrefs opts <$> getArgs
       >>= Opts.handleParseResult
diff --git a/src/Niv/GitHub/API.hs b/src/Niv/GitHub/API.hs
--- a/src/Niv/GitHub/API.hs
+++ b/src/Niv/GitHub/API.hs
@@ -15,6 +15,7 @@
 import qualified Data.Text.Encoding as T
 import Data.Text.Extended
 import qualified Network.HTTP.Simple as HTTP
+import Niv.Logger
 import System.Environment (lookupEnv)
 import System.Exit (exitFailure)
 import System.IO.Unsafe (unsafePerformIO)
@@ -80,7 +81,7 @@
 defaultRequest :: [T.Text] -> IO HTTP.Request
 defaultRequest (map T.encodeUtf8 -> parts) = do
   let path = T.encodeUtf8 githubPath <> BS8.intercalate "/" (parts)
-  mtoken <- lookupEnv "GITHUB_TOKEN"
+  mtoken <- lookupEnv' "GITHUB_TOKEN"
   pure
     $ ( flip (maybe id) mtoken $ \token ->
           HTTP.addRequestHeader "authorization" ("token " <> BS8.pack token)
@@ -134,33 +135,66 @@
 
 |]
 
+-- Some environment variables may have different meanings (see for instance
+-- https://github.com/nmattia/niv/issues/280)
+-- For ambiguous ones, we prepend NIV_.
+--
+warnGitHubEnvVars :: IO ()
+warnGitHubEnvVars =
+  mapM_
+    warnEnvVar
+    [ "GITHUB_INSECURE",
+      "GITHUB_PATH"
+    ]
+  where
+    warnEnvVar vn = lookupEnv (T.unpack vn) >>= \case
+      Nothing -> pure ()
+      Just {} -> do
+        twarn $
+          T.unwords
+            [ "The environment variable",
+              vn,
+              "was renamed to",
+              "NIV_" <> vn
+            ]
+
+-- | Like lookupEnv "foo" but also looks up "NIV_foo"
+lookupEnv' :: String -> IO (Maybe String)
+lookupEnv' vn = lookupEnv vn >>= \case
+  Just x -> pure (Just x)
+  Nothing -> lookupEnv ("NIV_" <> vn)
+
 githubHost :: T.Text
 githubHost = unsafePerformIO $ do
-  lookupEnv "GITHUB_HOST" >>= \case
+  lookupEnv' "GITHUB_HOST" >>= \case
     Just (T.pack -> x) -> pure x
     Nothing -> pure "github.com"
 
 githubApiPort :: Int
 githubApiPort = unsafePerformIO $ do
-  lookupEnv "GITHUB_API_PORT" >>= \case
+  lookupEnv' "GITHUB_API_PORT" >>= \case
     Just (readMaybe -> Just x) -> pure x
     _ -> pure $ if githubSecure then 443 else 80
 
 githubApiHost :: T.Text
 githubApiHost = unsafePerformIO $ do
-  lookupEnv "GITHUB_API_HOST" >>= \case
+  lookupEnv' "GITHUB_API_HOST" >>= \case
     Just (T.pack -> x) -> pure x
     Nothing -> pure "api.github.com"
 
+-- For these two we prepend NIV_ to the variable name because the variable
+-- names can have different meanings, see
+-- https://github.com/nmattia/niv/issues/280
+
 githubSecure :: Bool
 githubSecure = unsafePerformIO $ do
-  lookupEnv "GITHUB_INSECURE" >>= \case
+  lookupEnv "NIV_GITHUB_INSECURE" >>= \case
     Just "" -> pure True
     Just _ -> pure False
     Nothing -> pure True
 
 githubPath :: T.Text
 githubPath = unsafePerformIO $ do
-  lookupEnv "GITHUB_PATH" >>= \case
+  lookupEnv "NIV_GITHUB_PATH" >>= \case
     Just (T.pack -> x) -> pure $ fromMaybe x (T.stripSuffix "/" x) <> "/"
     Nothing -> pure "/"