Resonant tunneling measurements are used to probe the inhomogeneous strain in individual SiGe quantum dots. Current–voltage characteristics of strained Si/SiGe resonant tunneling diodes of diameterD⩽0.25 &mgr;mexhibit additional fine quasi-periodic structure in the resonant peaks. The fine structure is consistent with lateral quantization in the SiGe quantum well due to in-plane confining potentials arising from inhomogeneous strain, which we calculate by finite element techniques for variousD. Quenching of the fine structure by a magnetic field is consistent with the effective length scale of the strain-induced potential. ©1998 American Institute of Physics.