Exposure to acute psychosocial stress has been shown to affect moral decision-making, though little is known about potential gender differences or effects of personality. In two within-subjects design studies, 179 healthy men and women (N = 99 in Study 1, N = 80 in Study 2) were exposed to the Trier Social Stress Test (TSST) and a non-stress control condition (resting period) on two testing days in random order. After stress/resting, moral decision-making was assessed by the Everyday Moral Conflict Situations (EMCS) Scale (Singer et al., 2019), which requests altruistic versus egoistic responses to everyday moral conflict scenarios with varying closeness of target persons. We investigated effects of acute stress, social closeness, participants' gender, and the a priori selected personality traits agreeableness, empathy, and social desirability on everyday moral decision-making. Despite high statistical power, we could neither confirm the hypothesized effects of acute stress nor social closeness on EMCS scores in both samples. However, our data revealed a prosocial impact of acute stress on everyday moral decisions rather in females than males as well as effects of agreeableness and social desirability. Salivary alpha-amylase (sAA) levels in Study 1 and cortisol levels in females in Study 2 were significantly correlated with higher EMCS scores after acute stress exposure. Additionally, lower anticipatory subjective stress responses were associated with more altruistic decisions. Moreover, we found positive relationships between hypothetical moral decision-making and real prosocial behavior (opportunity for a charitable donation). In sum, due to methodological differences compared to previous between-subjects design studies, it might not be justified to rule out effects of acute stress on everyday moral decision-making based on the current within-subjects results. Nevertheless, the present data suggest that specific personality traits like agreeableness might have a stronger impact on everyday moral decision-making than short term-exposure to acute stress.