diff --git a/README.md b/README.md
index ba0997e..3b777ed 100644
--- a/README.md
+++ b/README.md
@@ -44,7 +44,7 @@ Command line arguments
 
     FLAGS:
         -h, --help              Prints help information
-            --trust_identity    Trust the value in the X-Identity header to be an authenticated username.
+            --trust-identity    Trust the value in the X-Identity header to be an authenticated username.
                                 This only makes sense when Sausagewiki runs behind a reverse proxy which
                                 sets this header.
         -V, --version           Prints version information
diff --git a/src/main.rs b/src/main.rs
index cdb1cc6..49744c4 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -53,7 +53,7 @@ fn args<'a>() -> clap::ArgMatches<'a> {
                 Err(_) => Err("Must be an integer in the range [0, 65535]".to_owned())
             })
             .takes_value(true))
-        .arg(Arg::with_name("trust_identity")
+        .arg(Arg::with_name("trust-identity")
             .help("Trust the value in the X-Identity header to be an \
                 authenticated username. This only makes sense when Sausagewiki \
                 runs behind a reverse proxy which sets this header.")