Liquid crystal compositions which can improve the low .DELTA.n (refractive index anisotropy) of conventional liquid crystal compositions containing a silacyclohexane compound and which retain a low viscosity and hence show no decrease in response speed. Liquid crystal compositions having a high .DELTA.n of 0.13 to 0.25, a low viscosity of 30 cp or less, a low threshold voltage and a high voltage holding ratio can be obtained by adding thereto, as a required component, a compound having both a silacyclohexane ring and a tolan structure, or a miture of a compound having a silacyclohexane ring and a compound having a tolan structure.