  We study the stability under linear odd-parity perturbations of static
spherically symmetric black holes in Horndeski gravity. We derive the master
equation for these perturbations and obtain the conditions of no-ghost and
Laplacian instability. In order for the black hole solutions to be stable, we
study their generalized "Regge-Wheeler potential". It turns out that the
problem is reduced to an algebraic problem where three functions characterizing
the black hole should be positive outside the horizon to prove the stability.
We found that these conditions are similar to the no-ghost and Laplacian
instability conditions. We apply our results to various known solutions.
