This study validates Seufert's (2018, 2020) model of self-regulated learning as a function of task difficulty, learner resources, and cognitive load. The model suggests that self-regulation is optimal at moderate task difficulty, where resources and cognitive load are balanced. The study involved 67 participants who reported their cognitive and metacognitive strategy use for four exams of varying difficulty. Cognitive load and available resources (e.g., prior knowledge, interest) were assessed for each exam. Multilevel analysis revealed an inverted U-shaped relationship between task difficulty and cognitive strategy use, with increasing cognitive load mediating this relationship. For metacognitive strategies, a linear relationship was found. Learner resources showed competitive mediation, indicating that further mediators could be relevant. The study also examined the relationship between cognitive load and learner resources, finding a negative correlation. The results support the model's assumptions, showing that perceived task difficulty influences self-regulatory activities, with cognitive load and learner resources mediating this effect. The study highlights the importance of balancing task difficulty with learner resources and cognitive load to promote effective self-regulation.This study validates Seufert's (2018, 2020) model of self-regulated learning as a function of task difficulty, learner resources, and cognitive load. The model suggests that self-regulation is optimal at moderate task difficulty, where resources and cognitive load are balanced. The study involved 67 participants who reported their cognitive and metacognitive strategy use for four exams of varying difficulty. Cognitive load and available resources (e.g., prior knowledge, interest) were assessed for each exam. Multilevel analysis revealed an inverted U-shaped relationship between task difficulty and cognitive strategy use, with increasing cognitive load mediating this relationship. For metacognitive strategies, a linear relationship was found. Learner resources showed competitive mediation, indicating that further mediators could be relevant. The study also examined the relationship between cognitive load and learner resources, finding a negative correlation. The results support the model's assumptions, showing that perceived task difficulty influences self-regulatory activities, with cognitive load and learner resources mediating this effect. The study highlights the importance of balancing task difficulty with learner resources and cognitive load to promote effective self-regulation.