This study examined teachers' perspectives on using a mobile phone in the promotion of teacher ethics in Tanzania. It was informed by the qualitative approach, using a sample of forty-eight (48) respondents who were drawn through purposive and convenient sampling techniques. Data were sought through Focus Group Discussions (FGDs) and were subjected to thematic data analysis. Findings indicated that a handful of respondents perceived a mobile phone as a viable tool in the promotion of teacher ethics. Moreover, ownership and accessibility, popularity and ease of use, internet coverage and connectivity, as well as the ubiquitous nature of the device were the reasons given for their perceptions. However, teachers' lack of knowledge, attitude and beliefs, financial problems, limited network connection, and poor coordination and technical support were the anticipated challenges in using the device in the promotion of teacher ethics. Based on the noted potential of the device, the study recommends the need for Teachers' Service Commission in Tanzania to adopt and use the device so as to ensure wider coverage of ethical information and combat unethical conduct amongst teachers.