Background Despite Saudi Arabia’s free and well-established cancer care program, breast cancer incidence and mortality are rising. Husbands’ knowledge, and wives’ attitudes and practices related to breast cancer screening are not well understood in Saudi Arabia. Objective The aim of this study was to investigate husbands’ knowledge, and wives’ attitudes and practices related to breast cancer screening in Saudi Arabia. Methods This cross-sectional study collected data from 403 husbands in the holy city of Makkah through an online self-reported questionnaire over a period of 2 months, from May 6 to July 7, 2020. Tabulation, bivariate, and multiple regression analyses were the major tools used for data analysis. Multivariate logistic regressions were used to examine the association between husbands’ knowledge and wives’ behavior regarding breast cancer screening methods. Results Husbands’ knowledge score (a 1-point increase) was significantly associated with the wives’ utilization of mammograms (adjusted odds ratio [AOR] 1.089, 95% CI 1.024-1.159) and breast self-examination (AOR 1.177, 95% CI 1.105-1.255). Husbands’ knowledge also influenced the wives’ attitudes toward learning about breast self-examination (AOR 1.138, 95% CI 1.084-1.195). There was no significant association between husbands’ knowledge and wives’ utilization of clinical breast examination. However, richer husbands showed a socioeconomic gradient concerning their wives’ utilization of clinical breast examinations (AOR 2.603, 95% CI 1.269-5.341). Conclusions Overall, husbands’ knowledge of breast cancer influences wives’ attitudes and practices related to breast cancer screening methods in Saudi Arabia. Thus, interventions delivered to husbands might increase breast cancer awareness and survival.