It was assumed that the effect of motivational regulation strategies on achievement is mediated by effort management and moderated by intelligence. A sample of 231 11th and 12th grade German high-school students provided self-reports on their use of motivational regulation strategies and effort management and completed an intelligence test. Students' half-year grades (GPA) were assessed six months later. As expected, motivational regulation strategies were not directly related to GPA but showed positive effects on students' effort management which in turn predicted students' GPA. Intelligence and effort management were equally strong direct predictors of GPA. Also as expected, more intelligent students benefitted more from using some, but not all, motivational regulation strategies in terms of increased effort management. Implications of these findings regarding the effectiveness of motivational regulation strategies are discussed. (Contains 2 tables and 2 figures.)