There is growing consensus that a one-size-fits-all approach is poorly equipped to treat diverse symptoms and health outcomes impacting diverse populations. This has fueled a precision medicine approach across many medical subfields including psychiatry, where the goal is to tailor treatments to the individual or subgroups of people. An emerging trend in TMS studies—and neuromodulatory clinical research more generally—is to subgroup the treatment population into those likely to respond to treatment (e.g., “treatment responders”) and those likely to not show a response to the treatment (e.g., “treatment non-responders”). We begin by surveying different conceptualizations of “treatment response” and “treatment resistance,” arguing that the methods used to make the responder/non-responder subgrouping are somewhat arbitrary, often oversimplified, and may set too high of a bar for what is considered “adequate” or “clinically significant” improvement. We then explore the ethical implications of this subgrouping for participants seeking to undergo TMS treatment. For instance, those labeled “treatment responders” may develop unrealistic expectations about the success of TMS treatment. More ethical concerns arise when we consider how the “treatment non-responder” label is likely to fuel stigma and pessimism regarding one’s illness and may be used to rule out TMS as a treatment option for those that have been chronically battling disabling symptoms.