We present high-resolution images of three BL Lac objects (0814+425, 1823+568, 2254+074) taken with the WFPC-2 camera on Hubble Space Telescope (HST) as part of a study of BL Lacs from a complete radio-selected sample. In two cases we clearly detect the host galaxies while the third BL Lac (0814+425) is unresolved. The host galaxy of 2254+074 is a moderately bright elliptical, while the inferred luminosity of the host galaxy for 1823+568 is at the high end of the range for previously known BL Lac hosts. The lack of detection of a host galaxy for 0814+425 calls into question the validity of its low reported redshift. Comparison of the HST data with subarcsecond ground-based R-band images shows excellent agreement on the largest scales, while on smaller scales only HST detects the galaxy significantly above the nuclear light. In the case of 2254+074, the high resolution of HST allows us to establish that the host galaxy is an elliptical.