An organic light-emitting device includes a first electrode; a second electrode opposite to the first electrode; and an organic layer between the first electrode and the second electrode, and the organic layer including an emission layer that includes at least one silane-based compound represented by Formula 1 below and at least one anthracene-based compound represented by Formula 20 below. wherein, in Formulae 1 and 20 above, R1 to R6, R11 to R16, L1 to L4, Ar1, Ar2, a, b, c, d, i, j, l, k, and n are further defined.