["Economica, EarlyView. ", "\nAbstract\nIt is well‐known that the wealthier are less likely to have Left‐leaning political preferences. In addition, we consider here the role of the individual's starting position, and in particular their upward social mobility relative to their parents. In 18 waves of UK panel data, both own and parental social status are independently negatively associated with Left‐leaning voting and political preferences; given their own social status, the upwardly mobile are therefore more Left‐wing. We replicate these findings using US data, and show that in both countries, the choice of specification when controlling for the respondent's own current status is crucial and may explain some of the mixed findings on mobility and political preferences in the existing literature.\n"]