In this paper, the author uses a generalized set-valued derivative and a special notion of degree for Lipschitz functions from \({\mathbb{R}}^ n\) into \({\mathbb{R}}^ n\) to study the ontoness of \(f\). Under suitable assumptions, certain existing results dealing with \(Df\) when \(f\) is \(C^ 1\) are extended to the generalized derivative \(\partial f\) of \(f\) whenever \(f\) is Lipschitzian.