Objectives: The objective of this study was to complete research about contraception and the consequences of unwanted pregnancy in Zanzibar, and to disseminate research findings to in-country champions, policy-makers and practitioners. Methods: This multi-method study in the semi-autonomous archipelago region of Zanzibar, Tanzania included five components: semi-structured group discussions with men and women in five communities, in-depth interviews of health care providers and other key informants, semi-structured interviews with women who have had abortions, and a hospital-based structured interview with patients receiving post-abortion care. Results: Barriers to contraceptive use for married women included men’s desire for large families; the belief that God determines family size; fear of contraception’s consequences (including infertility, cancer, and intolerable side-effects); insufficient knowledge about benefits of contraception; tensions between men’s and women’s responsibilities over reproduction; and worries that contraceptive use encourages women to have extra- and premarital sex. Men and religious leaders have little knowledge about contraceptive use even though they hold significant decision-making power about it. For unmarried women in Zanzibar, using contraception has several negative consequences: admission of sexual intercourse, resultant hostility from providers, side effects, and possibly future health problems. For unmarried women, hiding sexual intercourse precludes choosing contraception. Conclusions: While many Zanzibaris agree about avoiding pregnancy at certain times in life, women’s ability to use contraception is limited by norms around gender, sexuality and religion. To overcome fears about contraception’s health risks and side effects, men and women require high quality contraceptive counseling and positive examples of successful contraception use. To change social norms around contraception, dialogue about the safety and morality of contraception needs to include men and religious leaders. Many unmarried women expose themselves to possible bad consequences of pregnancy over certain bad consequences of using contraception. Until now, social norms against sexual intercourse among unmarried women have stifled discussion about contraceptive use in this group, and change in this arena represents the greatest challenge for policy makers and health care providers.