Increasing work engagement (WE) for worker health and turnover prevention has gained attention recently. Work-family conflict (WFC), which includes Work Interference with Family (WIF) and Family Interference with Work (FIW), is negatively associated with WE. The effects of WIF/FIW on WE are not fully understood. This study examined the longitudinal associations of WIF/FIW on WE by gender and household composition among employees. We conducted web-based surveys in 2020 and 2021, targeting full-time workers of a single private company (N = 3,437). The analysis included 425 respondents who completed two surveys. Multiple regression analyses stratified by gender and household composition were conducted, with WE at 1 year as the dependent variable and baseline WIF/FIW as independent variables. Higher WIF tend to be associated with lower WE (men in single-person households (SP): B = -0.07 [95% CI: -0.27, 0.14]
men in multi-person households (MP): B = -0.01 [95% CI: -0.12, 0.10]
SP women:B = -0.02 [95% CI: -0.31, 0.27]
MP women: B = -0.06 [95% CI: -0.25, 0.14]). The association between FIW and WE tended to be present only for women
higher FIW tend to be associated with lower WE (SP women: B = -0.03 [95% CI: -0.37, 0.30]
MP women: B = -0.06 [95% CI: -0.34, 0.21]). WIF, such as work-related stress, may reduce the energy available for personal activities among all workers. FIW, such as household tasks, may diminish the energy devoted to paid work, particularly among women living with family.