The family stress model (FSM) suggests that stress, particularly economic stress, hinders effective parenting. Expanding on the FSM, the present study examined not only the economic stress but also the general stress and several contexts that may promote stress-namely, physical health, mental health, socioeconomic status, employment status, and marital status. The present study also expanded the FSM to examine parenting of sibling groups. Ineffective parenting of sibling groups was conceptualized as greater parental differential treatment (PDT). A number of moderating variables were also considered. Multilevel meta-analysis models were used to test hypotheses. Across models, data came from 6,003 effect sizes, nested within 59 sources, nested within 16 unique samples (all coming from 8 published studies and 11 raw data sets). Results showed main effects for only parents' general stress and parents' mental health. More stress and poorer mental health were linked with greater amounts of PDT. Additionally, poorer physical health was linked to greater PDT but only when PDT involved positive parent-child interactions. As a whole, findings suggested that actual feelings of stress and psychological distress may show stronger links with PDT than contexts that merely have the potential to cause stress. Caution is warranted, however, as effect sizes were generally small and some models were based on predominantly Caucasian samples. Future research on the FSM and PDT should focus on actual experiences of stress and further consider the moderating role of domains of parenting. (PsycInfo Database Record (c) 2022 APA, all rights reserved).