[en] In this paper, we study the N-N and N-Δ spin-orbit forces using the quark model. The results are: (1) The N-N spin-orbit force is attractive for the triplet state with odd parity. This feature is qualitatively in agreement with the phenomenological potential determined by fitting the N-N scattering data. (2) The direct terms of the Δ-N spin-orbit force are mainly attractive and the exchange terms of that are attractive for the cases of ST = 12 and 21, repulsive for the cases of ST = 11 and 22. All these results may be useful to understand the properties of the N-Δ spin-orbit force