In the West, the style of a woman’s dress is perceived as a cue to her sexual behavior and influences the likelihood that a man will initiate conversation with the woman or offer her assistance. Hijab, or Islamic veiling, varies in the extent to which it reveals skin and body shape; the style a woman adopts affects her attractiveness to men. To test whether women who wear more liberal or conservative forms of hijab are more likely to be offered help by men, we observed Iranian motorists in a ‘hitchhiking’ situation. Here we show that a young female confederate, standing beside a road and in view of motorists but not actively soliciting assistance, was more likely to be offered a ride when she wore a headscarf and close-fitting garments (liberal dress) rather than a full body veil (chador, conservative dress). When the woman wore liberal dress, 21.4% of motorists offered a ride; only 3.9% of motorists offered a ride to the woman when she wore conservative dress—a significant difference. All drivers were men. This small to medium effect is substantially larger than those reported in similar studies in Europe, and extends previous research on male helping behavior and female attractiveness to Iran, a nation where courtship behavior and dress are constrained by stricter social mores and laws than apply in the West.