Recently, research considering SRL among primary school students has increased since it has been acknowledged that even young students can regulate their learning. However, in-depth and longitudinal information regarding upper primary school children's SRL is still lacking, especially of students at risk of school failure. Through a longitudinal multiple case study eight at-risk students were followed during two successive school years by using think-aloud protocols (six measurement occasions). The results confirm that at-risk upper primary students do engage in SRL, however on a rather superficial level. Moreover, their strategy use remained rather stable over time. Furthermore, differential results in the Sudoku and text studying task confirm that SRL can vary across tasks and domains. Regarding the assessment of SRL, the current study illustrates that think-aloud protocols are valuable tools to provide in-depth information, while also indicating the need for a multi-method design, especially in order to grasp motivational aspects of SRL.