The role of sign language interpreter is important to help both Deaf and hearing individuals to communicate in educational, medical, legal, and social settings. Their practice though is laden with ethical challenges especially in regard to level of confidentiality and impartiality. Confidentiality helps in keeping the sensitive information presented in the process of interpreting the messages confidential and impartiality means that the interpreter should be neutral and unbiased when delivering the messages. Pre-existing social relationships, cultural expectations, and lack of professional guidance are some of the factors that tend to challenge these responsibilities, particularly where the context is Nigerian. This paper explores ethical dilemma encountered by sign language interpreters with the implications on the trust, effectiveness in communication, and practice of the profession. Professional training, ethical practices, and suggestions are presented to support professional training, maintain confidentiality, and impartiality in sign language interpreting to improve the quality and integrity of sign language interpreting.