The Reward Positivity (RewP) is a neurophysiological marker of reward sensitivity that has been found to be impacted in depression. However, there have been some mixed findings regarding the relationship between the RewP and depression, suggesting there are other factors which impact this relationship. The current study investigated how the demographic factors of sex, age, and socio-economic status might moderate the RewP-depression relationship, and examined if these effects generalize across three different inventories for symptoms of depression. 194 people were recruited by random digit dialing (55.2% male, mean age = 51.34 years, mean monthly income = $6625.95). They completed the SCID, HAM-D, and IDAS measures of depression, and an EEG session in which they did a random guessing task to elicit the RewP. We found that there was a trend-level interaction of a moderate effect size between symptoms of depression, age, and sex in predicting RewP amplitude. Further exploration of this interaction revealed that for females, there was an interactive effect between age and symptoms of depression, such that for younger females, increased symptoms of depression were associated with a blunted RewP, and lower symptoms of depression were associated with an enhanced RewP. These effects were specific to the SCID, but did not generalize to the HAM-D or IDAS. Moreover, there was no interactive effects between age and depression symptoms for males, nor did SES interact with depression and other demographic factors in predicting the RewP. This study provides evidence that demographic factors can impact the strength and nature of the relationships between the RewP and depression, and that future researchers might wish to over-sample younger females when investigating other moderating factors of the RewP in order to increase power.