Generalised unitarity techniques are used to calculate the coefficients of box and triangle integral functions of one-loop gluon scattering amplitudes in gauge theories with N < 4 supersymmetries. We show that the box coefficients in N=1 and N=0 theories inherit the same coplanar and collinear constraints as the corresponding N=4 coefficients. We use triple cuts to determine the coefficients of the triangle integral functions and present, as an example, the full expression for the one-loop amplitude A^N=1(1^-,2^-,3^-,4^+,..,n^+).