Glass-ceramics containing ferroelectric CsLiB6O10 crystals were prepared by heat treating Cs2O–Li2O–B2O3 glasses. Second harmonic generation (SHG) was observed from samples prepared by two-step heat treatment (nucleation and growth); however, the intensity was rather weak. On the other hand, one-step heat treatment by the addition of a small amount of TiO2 to the glass resulted in the glass-ceramics containing small single crystal-like CsLiB6O10 particles. The strongest SHG observed was comparable with that of Y-cut quartz. The preferred orientation of precipitated CsLiB6O10 crystals was attributed to the occurrence of SHG from the glass-ceramics.