This study describes women's menstrual health needs at work in Uganda and explores the associations between unmet needs and women's work and wellbeing. We undertook a cross-sectional survey of women working in marketplaces, public primary schools, and health care facilities in Mukono district, central Uganda. Survey questions were designed to capture women's experiences of managing menstrual bleeding, pain, social support, and the social environment. A total 435 women working in markets, 45 teachers and 45 health care facility workers participated. Of these, 15% missed work due to their last period, and 41% would prefer not to work during menstruation. Unmet menstrual health needs were associated with consequences for women's work and psychological wellbeing. Experiencing menstrual pain (aPR 3.65 95%CI 1.48-9.00), along with the use of improvised menstrual materials (aPR 1.41 95%CI 1.08-1.83), not feeling comfortable to discuss menstruation at work (aPR 1.54 95%CI 1.01-2.34) and the expectation that women should stay home when menstruating (aPR 2.44 95%CI 1.30-4.60) were associated with absenteeism due to menstruation. In contrast, not having menstrual management needs met (aPR 1.45 95%CI 1.17-1.79) and the attitude that menstruating women are dirty (aPR 1.94 95%CI 1.50-2.51), along with pain (aPR 1.59 95%CI 1.12-2.24) and norms around absenteeism were associated with wanting to miss work. After adjustment for age and poverty, unmet menstrual management needs (b = -5.97, 95%CI -8.89, -2.97), pain (b = -3.89, 95%CI -7.71, -0.08) and poor social support (b = -5.40, 95%CI -9.22, -1.57) were associated with lower wellbeing measured using the WHO-5. Attitudes that menstruation should be kept secret (b = 4.48, 95%CI 0.79, 8.17) and is dirty (b = 4.59, 95%CI 0.79, 8.40) were associated with higher wellbeing. Findings suggest that supporting care for menstrual pain, addressing secrecy surrounding menstruation and the perception of menstruation as dirty, and improving access to materials and facilities for managing menstrual bleeding are avenues for programs and policies to support working women.