Personality traits such as conscientiousness and impulsivity correlate with temporal discounting, the degree to which individuals discount the value of future relative to present rewards. These variables have, in turn, been hypothesized to relate to income inequality in the United States. A key but untested assumption of this hypothesis is that the association among these variables is distinct across socioeconomic classes. The purpose of the present research is to test that assumption. N = 1,100 adults with annual income ranging from at or below the poverty line ($0 - $20,000) to upper-middle class ($200,000+) completed personality measures and a measure of temporal discounting. The results of our preregistered analyses indicated a positive association of income with trait planfulness, and a negative association with trait impulsivity and one parameter of temporal discounting that captures a bias to prefer sooner rewards to a greater degree if they are delivered that day. Our results can inform psychological theories of inequality and a broader conversation about effective public policy.