The processes and perceptions of students' self-regulated learning are not easily measured. Thus, research has presented and suggested numerous ways in which these processes and perceptions of self-regulated learning can be investigated and assessed. Accordingly, this study aims to assess whether training in how to regulate one's learning is related to students' growth patterns regarding their reported self-regulated learning activity over time. This study also investigates whether this type of training has an impact on students' reflective ability and academic performance. To reach these goals, we examined whether students' use of a diary task - developed by interviewing primary school students (n?=?43) and validated with exploratory (n?=?78) and confirmatory (n?=?83) factor analysis - would capture change in students' reported self-regulated learning activity and reflective ability during training in how to regulate one's learning (students: n?=?100; diary task entries: n?=?1,000). Students' academic performance was assessed with an oral and vocabulary task. Results from multilevel linear modeling revealed different growth rates of reported self-regulated learning activity over time between students who experienced training and students who did not. Furthermore, pre and posttest results revealed that the students who experienced the training reported their reflections more autonomously and specifically in their diary task and had better academic performance than students who did not. These results demonstrate how the diary task captured change in students' perceptions, validating it as a monitoring tool. Lastly, implications for practitioners are discussed and suggestions for future studies are proposed.