Intimate partner violence (IPV) is the most common form of violence faced by women globally. The prevalence of lifetime experiences of physical and sexual IPV is estimated to range from 15% to 71%. IPV where a perpetrator is a male current or ex-partner is an existing gender problem in many countries. Millions of women in Africa especially those living in informal settlements are affected by IPV. The most common form of IPV is physical, psychological and sexual abuse. Several studies conducted in Tanzania on IPV have not yet examined the characteristics of perpetrators of such violence acts in informal settlements. This cross-sectional study aimed to examine IPV perpetrators’ characteristics and their association with IPV perpetration in informal settlements. Multi-stage sampling was applied. Random sampling was used to obtain a sample of 300 women living in informal settlements of Iringa Municipality. A survey was used to collect data and SPSS version 20 was used for analysis. A χ2 test was used to assess the association between the outcome variable and a set of exposure variables. Ethical clearance was obtained from Muhimbili University Institutional Review Board. Written consent was sought before participation in the study. IPV perpetrators’ socio-demographic characteristics were age, marital status, marriage type, occupation and level of education. Alcohol intake characteristics were alcohol intake status and intake frequency, where 62.7% were reported to take alcohol many times. Marital status, level of education, occupation, alcohol intake status and frequency of alcohol intake were linked to physical IPV ( p < 0.005). Perpetrators’ characteristics associated with both sexual and emotional IPV were marital status, alcohol intake and the frequency of alcohol intake ( p < 0.005). IPV perpetrators’ socio-demographic characteristics mainly marital status, level of education, alcohol abuse and alcohol intake frequency have a major contribution to the burden of IPV in Iringa municipality. Low level of education and occupation status as business persons are at higher risk of being violent physically, sexually and emotionally. Men aged between 31 and 50 years are more violent in all forms than others. Community IPV prevention interventions focusing on both men and women will be helpful since IPV perpetration may not only be initiated by men but also by women who may lack life and relationship coping skills. More research is important focusing on IPV perpetration attitude and perceptions from men and women perspectives to inform IPV prevention and management.