While students’ interpersonal competence beliefs and perceived classroom goal structures have been investigated to large extent, less in known about intrapersonal (situation-specific) beliefs. In this study we investigated primary school students’ intrapersonal competence beliefs (success evaluation, understanding, effort, difficulty) during lessons over one week, and interpersonal beliefs (ability, effort, difficulty), and related these to interpersonal perceived classroom goal structure (mastery and performance structure). In total 322 students in Year 5 and 6 (mean age 10.5 years) filled in electronic questionnaires during lessons over one week (between 4 to 37 learning episodes in total, M = 18.7; SD = 5.0). Multilevel Confirmatory Factor Analysis in MPLUS suggested that intrapersonal effort and competence (success evaluation, understanding) were distinguishable from difficulty. The relationships between intrapersonal effort, difficulty and competence varied substantively across students (i.e., interpersonal differences in intrapersonal correlations). Random slope models showed that students who perceived a high performance goal structure perceived difficult tasks as obstacles (exerting less effort) rather than challenges (exerting more effort). In contrast students who perceived both a high mastery and performance goal structure sensed that they increased effort up to the limit of their ability.