The notable increase in the number of hours devoted to teaching practicums is a direct consequence of the recent wave of reforms to initial teacher training programs in North America and elsewhere in the world. These reforms, aimed at professionalizing teaching, granted more importance to the supervising teacher (ST) without really consecrating the role. Although the influence these teachers have on the professional development of future teachers is already perceived as very important, they do not always receive the consideration they deserve. However, this influence raises questions about the quality of the learning experiences student teachers are receiving during practicums, and concerns about the selection of ST and their pedagogical supervision training, an aspect that is still largely neglected in the training of future teachers. This article consists of a review of the scientific literature about teacher training, with ST being the main actors who fulfil specific functions requiring skills that are both distinct from and complementary to regular teaching skills. The authors support the idea that investing more resources in ST training is one way to raise the training potential of the practicum and ultimately improve the overall competence of the teaching corps.