The participation of married women in decision-making in all spheres of household development, including health care, purchases, and visiting their relatives, is important for households, communities, and the nation at large. Designing successful and suitable interventions requires understanding the factors associated with making three major household decisions on their health care, major household purchases, and visits to family or relatives among married women between 15-49 years. The study aimed to determine social-demographic and economic factors associated with decision-making roles among married women in Tanzania. The data for this study were obtained from the 2022 Tanzania Demographic and Health Survey and Malaria Indicator Survey (2022 TDHS-MIS) by visiting https://www.dhsprogramme.com. Data were analysed using STATA Version 16, whereby a multinomial regression model was chosen as the statistical approach. The study showed that age, education level of married women and their husbands, women’s residence, wealth index, watching television, listening to the radio, working status, and number of household members were identified as the factors affecting women’s decision- making in households regarding health care, significant purchases, and visiting their family and relatives. The study concludes that the married women’s decision-making on health care, major household purchases, and visiting their family or relatives in Tanzania was 52%, which is low compared to sustainable development goal 5 on achieving gender equality and empowering all women and girls, and the Maputo Protocol, which guarantees extensive rights to African women and girls, including social equality with men. Therefore, through the Ministry responsible for women, the government should address social norms and cultural practices that limit women’s decision-making power through community engagement and education provision. Also, mechanisms should be established to monitor and evaluate the effectiveness of policies and programmes to enhance women’s decision-making power.