This paper examines the theory of Multiple Intelligences (MI) as the most viable and effective platform for 21st century educational and instructional methodologies based on the understanding of the value of diversity in today's classrooms and educational institutions, the unique qualities and characteristics of individual learners, the opportunities that arise from applying the ideas of multiple intelligences, the need for flexibility and adaptation in a global society, and the increasing demand for accountability at all levels of education. Several definitions of intelligence are presented and the author examines the theories of Sternberg and Goleman as supportive of the philosophy of multiple intelligences being the most effective for 21st century educational and curricular platform. The author sees the value of MI theory as broad enough to facilitate 21st century understanding of education and intelligence in so much as diversity and technology have fueled changes in the definitions and requirements of individuals with regard to pedagogy. In putting forth a strong argument of multiple intelligences (MI) being a strong platform for effective educational and instructional methodologies in 21st century classrooms and schools, the author also examines opposing views and attempts to counteract such with supporting literature, examples, and ideas. (Contains 1 figure and 1 table.)