There is limited information about the influence of partners on medical male circumcision (MMC) uptake. This study aimed to evaluate attitudes, knowledge, and preferences about MMC among men and their partners, and their relative impact on male readiness to undergo the MMC procedure. Male participants (n = 354) and their partners (n = 273) were recruited from community health centers in Lusaka, Zambia. Men reported their readiness to undergo MMC, and both men and women were assessed regarding their attitudes and knowledge regarding MMC. Men who had discussed MMC with their partners, those who endorsed MMC for HIV risk reduction, and those viewing MMC as culturally acceptable reported increased readiness to undergo MMC. Additionally, endorsement of MMC by female partners was associated with increased men's readiness. Results support promotion of cultural acceptability of MMC, and efforts to increase MMC uptake may benefit from incorporating partners in the decision making process.