The purpose of this paper was to investigate the psychosocial consequences of transitioning into informal caregiving, and to investigate this association in male and female caregivers with a longitudinal design. Longitudinal panel data from the population-based German Ageing Survey (wave 2014, 2017) were used. The complete sample included up to 13,333 observations (N = 8658) pooled over waves 2014 and 2017. In total, 2.56% of the complete sample transitioned into informal caregiving (N = 547). Individuals who transitioned into informal caregiving, were on average aged 66 years and 54.48% of these participants were female. Wellestablished scales were used to assess the psychosocial outcomes of network size, loneliness and social isolation, depressive symptoms, as well as positive and negative affect. Transitioning into informal caregiving was used as the main predictor. Sociodemographic characteristics and physical health were controlled for. Results of fixed effects regression analyses showed that transitioning into informal caregiving was significantly associated with increased network size (b = 0.35, p < 0.05), increased depressive symptoms (b = 0.63, p < 0.05) and increased negative affect (b = 0.08, p < 0.001). When stratifying the sample by gender, the results showed increased network size (b = 0.43, p < 0.05), depressive symptoms (b = 0.93, p < 0.01), and loneliness (b = 0.06, p < 0.05) among male caregivers, while female caregivers reported increased negative affect (b = 0.10, p < 0.001). The study's results extend previous research by showing that transitioning into informal caregiving is mainly associated with negative psychological outcomes. Additional analyses suggest that female and male caregivers experience different psychosocial consequences. Thus, gender should be taken into consideration when investigating informal care and its outcomes, and support should be tailored specifically to the needs of female and male caregivers.