Achievement evaluation in school contexts may be considered as a kind of social judgment, which is affected by social and moral determinants since it is not merely an estimation of pupils' accomplishment (Dompnier, Pansu, & Bressoux, 2006; Weiner, 2003). Teachers' judgments have been investigated starting from the analysis of two theoretical approaches: the norm of internality (Dubois, 2003), and the attributional approach to social motivation (Weiner, 2006). In order to study the social valorization of internal explanations referring to effort in school context, an empirical research has been conducted. Our study investigates how teachers evaluate fictitious pupils, which are supposed to explain events by means of different types of causal explanations. According to our results, pupils providing effort-based explanations receive more positive judgments. Findings are discussed by considering effort as a key principle of school environments. (Contains 4 notes.)