In this paper, we introduce a new instrument to assess the components of adolescents’ motivation to learn: the “Inventaire de motivation et volition scolaires”. The originality of this instrument is the integration of components of motivation based on the self-determination theory (Ryan & Deci, 2000), and volitional aspects (procrastination and motivational self-regulation strategies). Two studies, conducted with 166 and 661 French speaking high school students (15 to 19 years old) in the canton of Geneva, in Switzerland, are reported in order to investigate the internal validity (dimensional analyses, internal consistency estimation, and link to social desirability) and external validity (nomological network) of the instrument. The Inventaire de motivation et volition scolaires will be useful as an assessment tool for teachers and as a research instrument on motivational topics.