The effect of dense sprays on particle size measurement by laser-diffraction based techniques is examined for lag-normal distributions of particles in multidimensional media. A Monte Carlo modeling technique is used to simulate scattering of light by particles, and general scattering phenomena are included by using Mie theory. The measurement errors in particle size distribution parameters due to multiple scattering are analyzed and compared to corrections previously presented for homogeneous planar media. The errors for measurements in homogeneous cylindrical media equal those for planar media with the same optical depth, but the cylindrical geometry requires the use of a scaled obscuration. Specifically, the obscuration is dependent on the size of the laser beam relative to the cylinder. Nonhomogeneities are examined in planar media and found to have no effect on the measured size distribution or obscuration. In nonhomogeneous cylindrical media, measurement errors in particle size distribution parameters due to multiple scattering are shown to be predicted by planar corrections for line-of-sight measurements in sprays. Simulations done with wide beams result in measured distributions that are within acceptable accuracy limits of equivalent homogeneous results, and multiple scattering biases can be corrected as if the medium were homogeneous.