Carol Ann Tomlinson

Differentiation is simply a teacher attending to the learning needs of a particular student or small groups of students, rather than teaching a class as though all individuals in it were basically alike.

Differentiation is classroom practice that looks eyeball to eyeball with the reality that kids differ, and the most effective teachers do whatever it takes to hook the whole range of kids on learning.

A teacher in a differentiated classroom does not classify herself as someone who ‘already differentiates instruction.’ Rather that teacher is fully aware that every hour of teaching, every day in the classroom can reveal one more way to make the classroom a better match for its learners.