This study investigates gendered patterns in financial justification behaviors through the lens of the popular social media phenomenon known as “girl math.” Drawing on theories of mental accounting, payment depreciation, and justification-based decision-making, the research explores how individuals rationalize spending across gendered and neutral purchase categories. Using a survey of over 1000 respondents and a mixed-effects modeling framework, the analysis reveals that women exhibit stronger justification tendencies for female-centric purchases, while men display similar rationalization patterns for male-centric categories—challenging the stereotype that such behaviors are uniquely female. The study also finds that delayed consumption and category alignment significantly influence justification scores. These findings suggest that “girl math” reflects broader behavioral patterns shared across genders, rather than an inherently gendered phenomenon, thereby questioning the cultural framing of female financial irrationality.