Masjid Al-Mustafa is a mosque in Waterbury, Connecticut, owned and operated by the Islamic American Society of Connecticut (IASC), a non-profit organization registered in the state since 2007. The three-floor building officially opened on May 19, 2017, and includes a main-level prayer space for men and women, classrooms on the second floor, and a community center in the basement. The mosque provides prayer services, educational classes, social activities, an Islamic school, and funeral services for the community.