A key debate in the psychology of ideology is whether leftists and rightists are psychologically similar or different. A long-standing view holds that left-wing and right-wing people are meaningfully different from one another across a whole host of basic personality and cognitive features. Scholars have recently pushed back, suggesting that left-wing and right-wing people are more psychologically similar than distinct. We review evidence regarding the psychological profiles of left-wing and right-wing people across a wide variety of domains, including their dispositions (values, personality, cognitive rigidity, threat-sensitivity, and authoritarianism), information processing (motivated reasoning and susceptibility to misinformation), and their interpersonal perceptions and behaviors (empathy, prejudice, stereotyping, and violence). Our review paints a nuanced picture: People across the ideological divide are much more similar than scholars sometimes appreciate. And yet, they differ-to varying degrees-in their personality, values, and (perhaps most importantly) in the groups and causes they prioritize, with important implications for downstream attitudes and behavior in the world.