Differentiation can begin with a single lesson, expand to a unit, and finally grow to be a natural part of a teacher’s daily practice. The Think-Tac-Toe, described in this article, can evaluate students’ learning during and at the conclusion of a unit. Prior to its creation, teachers should preassess students to be certain that the content of the Think-Tac-Toe will capture the array of readiness and skills present in the classroom. As with any new teaching skill, implementation is best achieved when teachers tackle a differentiation project of manageable size.