Children and youth from lower subjective socioeconomic status (SES) backgrounds are at a heightened risk of mental disorders. Online counseling is a valuable tool to reach those less likely to seek professional help, but its success across different SES backgrounds remains unclear. This study explores the association between subjective SES and online counseling outcomes. Children and youth (N = 2139) between 10 and 24 years-of-age received chat-based online counseling and reported on SES, negative feelings before and after the chat, and perceived helpfulness of the chat via an online assessment tool. The results of a latent change score model showed a significant association between SES and negative feelings before chatting, indicating that lower SES predicted more negative feelings (r = −0.26, p < .001). Further, SES was indirectly associated with the change in negative feelings from before to after counseling, mediated by the extent of negative feelings before the chat (β = 0.07, 95%CFI = [0.05–0.10]). Current findings extend research on online counseling programs in the context of SES. Despite higher counseling needs among low SES individuals, they do not benefit proportionally from existing online services in this sample. Future research should investigate barriers to help-seeking and implement specialized counselor training programs.