One of the greatest hurdles in the transition of transgender persons is that their voice, speech and communication are not congruent with their gender identity. In transgender women (trans women), speech therapy is the treatment of choice to develop a more feminine communication and must focus on these aspects the most salient in gender perception. According to the systematic review of Leung et al. (2018), intonation is a prosodic component that contributes to gender perception. However, it is not clear to what extent frequency changes in intonation patterns improve the gender congruence of the speech. Although intonation is commonly addressed in feminization speech therapy, the relation between gender perception and intonation remains unclear and empirical evidence of intonation training is lacking. In the first part of the project the relation between acoustic intonation parameters and gender perception is investigated using a listening experiment. The second aim is to investigate the short- and the longer-term effect of intonation training on vocal characteristics, listener perceptions and patient related outcome measures in trans women using a randomized sham-controlled trial. The content of the intonation training is selected based on a systematic review of Leyns et al. (2021). This research will lead to important new insights in speech feminization components and will have a major impact on evidence-based practice in speech therapy for trans women.