The objective of this study is to explore the perceptions of intern teachers and mentor teachers regarding the determinants of learning from success during the internship year. The study was conducted using semi-structured interviews with 37 teachers: 17 mentor teachers and 20 interns. Data analysis brought up the following themes: communication between intern, mentor and professional team; integrating learning from problems and learning from successes; differences due to subject-matter division and to personality gaps; identifying and analyzing factors leading to success; habit of mind; lack of professional esteem; and non-sufficient allocation of time for learning from success. Understanding how intern teachers and mentor teachers perceive the determinants of learning from success during the internship year could indicate whether and how this collaborative learning process can be nurtured and sustained.