The transverse diffusion coefficient is calculated by integrating the current derived from heterogeneous multigroup dipole theory in a finite, square system, along two opposite sides of the square cell. Use of response coefficients allows the result to be presented in relatively simple form, regardless of fuel element complexity. Subsequently, the buckling dependence is eliminated from the diffusion coefficient, or reduced to lowest order, making it consistent with the low order approximation represented by dipole theory. Results are compared with other methods and a numerical example is given.