This paper concerns the ethics of human neuromodulation using transcranial magnetic stimulation (TMS). We examine the challenges of modulating the brain with TMS through the research ethics lens and in clinical medicine for treating frank pathology, primarily in psychiatric diseases. We also consider contemporary issues raised in the neuroethics literature about managing unexpected findings, and relate these to TMS and to other frontier neurotechnology that is becoming openly available in the public domain. We argue that safety and informed consent are of paramount importance for TMS, but that personal values and sociocultural factors must also be considered when examining the promise of this technology and applications that ought to be highlighted for extra precautions.