Self-consistent-field theory is used to predict the center-of-mass distribution of spherical nanoparticles embedded in the lamellar phase of a diblock copolymer melt. The calculation is performed in the dilute limit, where the particle-particle interactions have a negligible effect on the distribution. We investigate how the distribution is affected by particle radius R, surface affinity Lambda N, diblock segregation chi N, diblock composition f, and invariant polymerization index (N) over bar. While the preferred location of the particles (i.e., interface or domain center) is primarily controlled by Lambda N, the degree of particle localization depends on several factors. Larger values of R, chi N, and (N) over bar all tend to produce narrower particle distributions.