Most financial firms are genuinely committed to improving gender balance among their senior executives. To that end, they have introduced a number of “women-friendly” programs, such as flexible hours, parental leave, and mentorship schemes. Helpful as they are, such measures do not fully address the problem, which also lies in the unconscious biases, expectations, and practices of organizational cultures, which have been created by predominantly male executives over decades. This HBR article, backed by recent research, explains what else needs to be done to fix this significant problem.