This paper is concerned with the oscillation of solutions of higher order nonlinear delay difference equations with forcing terms of the form δ nx(t)+f(t,x(t),x(σ(t)))=h(t), tϵI={0, 1, …}, where Δ is the forward difference operator defined by Δx( t) = x( t + 1) − x( t) and Δ m x( t) = Δ( Δ m−1 x( t)), m > 1. A necessary and sufficient condition is established under which every solution x(t) is oscillatory when n is even, and is either oscillatory or strongly monotone when n is odd. A sufficient condition for the oscillation of solutions of neutral type delay difference equations is also obtained.