Marital satisfaction is one of the ingredients of marital stability and is affected by a number of factors. A cross-sectional survey substantiated with qualitative studies was conducted so as to identify the major socio-demographic factors that influence the marital satisfaction of married couples among selected districts of Jimma Zone, Oromia, Ethiopia. Study participants of 240 randomly selected couples, either the wife or husband, were surveyed and key informant interview was held to collect evidences about the study objectives. As a result, variables such as level of education, number of children, spousal infidelity, marriage type, leisure spending, interest difference, openness among couples, and poverty have brought a statistically significant difference in marital satisfaction. Similarly, qualitative study participants noted that economic background, educational background, type of marriage, religious background, ethnic background, age difference, place of birth, religious discordant marriage, migration, adultery, early marriage, Khat abuse, in-laws interference, family size, sexual incompatibility and polygamous marriage determine the marital satisfaction of couples in the study area. Besides, the study found out the existence of differences on the factors that shape the marital satisfaction of urban and rural couples.