diff --git a/src/main.rs b/src/main.rs
index fbdfcd1..a2bce7e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -275,6 +275,11 @@ fn apply_args(cmd: &mut Command, args: &Expand, color: &Coloring, outfile: &Path
         color => line.arg(color.to_possible_value().unwrap().get_name()),
     }
 
+    for kv in &args.config {
+        line.arg("--config");
+        line.arg(kv);
+    }
+
     for unstable_flag in &args.unstable_flags {
         line.arg("-Z");
         line.arg(unstable_flag);
diff --git a/src/opts.rs b/src/opts.rs
index 8225bad..1e85a40 100644
--- a/src/opts.rs
+++ b/src/opts.rs
@@ -40,6 +40,10 @@ pub struct Expand {
     #[arg(long, value_name = "WHEN")]
     pub color: Option<Coloring>,
 
+    /// Override a configuration value
+    #[arg(long, value_name = "KEY=VALUE")]
+    pub config: Vec<String>,
+
     /// Unstable (nightly-only) flags to Cargo
     #[arg(short = 'Z', value_name = "FLAG")]
     pub unstable_flags: Vec<String>,