The purpose of current study was to extend the work of self-regulation by investigating the relationship between high school students, motivational regulation, their use of learning strategies and mathematics achievement. Subjects were 171 first year high school students (69 females and 102 males). Their average age was 14 years and 7 months. They were enrolled in 8 classes of public schools in Shiraz. The motivational Regulation Scale (MRS) and the Mathematics Learning Strategies Scale (MLSS) were used as measurement instruments. Factor analysis showed 5factors in MRS: Interest enhancement, performance self-talk, mastery self-talk, self-consequating and environmental control. Four factors of MLSS were: executive control strategies, descriptive-organized cognitive strategies, integrative-analytical cognitive strategies and help-seeking. Cronback alpha coefficients for these subscales varied from .58 to. 85. Analysis of research data showed positive significant correlations between motivational regulation strategies (except self-cons equating) and learning strategies. Multiple regressions showed that learning strategies is positively predicted by the use of interest enhancement, mastery self-talk and environmental control. The relation between performance self-talk and cognitive strategies for learning mathematics was negative. Hierarchical regression analysis revealed that performance self-talk and executive control strategies positively predict mathematics achievement. In general, these findings proposed that Iranian students use motivational and cognitive strategies in order to regulate their learning processes in mathematics. They activate their cognitive regulation mechanisms by the use of motivational regulation strategies. In addition, these evidences suggest that motivational strategies emphasizing learning outcomes have negative effects on learning strategies, but positive effects on mathematics achievement. These findings were interpreted in the light of self-regulation models. The applications for mathematics education were also discussed.