Bro, J. Motivational Attitude: This is a study of the Effects of Motivational Principles on Students' Attitudes towards Mathematics. The research question addressed is, how does purposefully crafting Geometry lessons using principles of motivation and engagement affect high school students' attitudes towards mathematics? Fennema and Sherman's validated questionnaires are used as a means to measure attitude, confidence, usefulness, anxiety, significant other perceptions, and effectance (motivation to master) in mathematics. Strategies and noted principles to increase motivation and engagement are used as a means to improve student attitudes towards mathematics. Orhun (2007) cites that teachers who recognize student differences in methods of learning will have a greater chance to connect the mathematics to their students in various ways, thus increasing their students' motivation to learn the subject. Similarly, students who understand the styles with which they learn best are more likely to approach learning with a better attitude and, in turn, become a stronger student.