||The purpose of this action research project was to determine whether the elements of motivational research in Goal Theory and Self-Determination Theory could enhance the Montessori mathematics curriculum to increase student motivation and achievement. This was accomplished by the creation of the MMRT model in which students were introduced to the elements of goal setting such as self-selected goals which were speciﬁc, measurable, meaningful, challenging, realistic and attainable with regular feedback. The study questions looked at how the MMRT model affected student motivation in large operation math work, how the MMRT model affected student attitudes toward their math work, and how the MMRT model affected students' levels of self-efficacy. The study group consisted of 23 upper elementary students at a preschool-9th grade public Montessori charter school located in the intermountain west. Study data were collected through parent and student surveys, classroom observations, student assessments, work records and student work samples. The data were analyzed using the constant-comparison method throughout the study. The results of the study showed that the elements of MMRT had a positive effect on student work, with increased numbers of student lesson requests and faster progression of the students through the math curriculum. Three groups of students were identified in the study based upon their initial motivational levels. Overall findings reveal that the higher the student's initial motivational level, the more likely they were to have increased motivation throughout the study.