We study the finite-Nc corrections to the next-to-leading order (NLO) Balitsky--Kovchegov (BK) equation. This contains correlators of six Wilson lines, which we express in terms of the two-point function using the Gaussian approximation. Numerically, the effects of these finite-Nc corrections on the NLO BK equation are found to be smaller than the expected 1/Nc^2 ∼ 10 percent. Corrections may be large for individual correlators, but have less of an influence on the shape of the amplitude as a function of the dipole size. There is an even smaller effect on the evolution speed as a function of rapidity.