Ethical concerns surrounding the use of punishment in applied behavior analysis are widely recognized (e.g., BACB, 2014; BACB, 2020; DiGennaro, Reed & Lovett, 2007). Comparatively little attention has been paid to ethical considerations regarding the use of extinction. Nonetheless, many of the same concerns that arise with regard to punishment are relevant to extinction. Ethical concerns have been raised regarding adverse side-effects associated with punishment (e.g., Cooper, Heron, and Heward, 2007). Similar concerns arise regarding extinction, with side effects including increases in problematic behaviors and the emergence of aggression (Lerman, Iwata, & Wallace, 1999). Ethical concerns about the limited efficacy of punishment (Cooper, Heron, and Heward, 2007) and that punishment fails to teach replacement behavior (Pokorski & Barton, 2021) may also arise with extinction-based approaches. Appropriate use of extinction requires accurate identification of functional reinforcers maintaining target behavior(s); however, research suggests minimal use of gold-standard function-based methodologies in common practice (e.g., Oliver, Pratt, & Normand, 2015). Concerningly, improper use of procedures such as planned ignoring are at high risk for adverse side effects, concerns which have also been raised by autism advocates (e.g. Just1Voice, n.d.). This paper discusses comparatively underappreciated ethical concerns surrounding the use of extinction.