Stepfamilies face unique challenges in managing finances, which can lead to relational issues such as financial infidelity. While research on financial infidelity in romantic relationships has progressed over the past decade, its occurrence in stepfamilies still needs to be explored. This study provides a conceptual framework to examine the interplay between stepfamily dynamics and genetic relatedness concerning financial infidelity. The study also addresses implications for financial and mental health professionals and provides practical applications they can use to help address this issue.