Work-life balance (WLB) practices are designed to support employee well-being and engagement, yet may trigger biased evaluations shaped by gender and age stereotypes. This study examined whether these stereotypes moderate the relationship between WLB practice use and perceived engagement. Using a dyadic survey design, 216 employees reported their WLB behaviors, while their managers rated engagement. No significant moderation effects were found, but trends suggested that WLB use was linked to slightly higher engagement ratings for women—especially younger women—and lower ratings for older men. These findings challenge traditional flexibility stigma assumptions by suggesting that women may not be penalized for using WLB practices, while men may still face prescriptive bias. The results highlight the nuanced ways in which identity-based stereotypes shape managerial evaluations and underscore the importance of inclusive, bias-aware approaches to WLB policy.