Teachers today must meet the needs of a variety of learners. In addition to the broad array of cultural differences and varying disabilities teachers encounter, their classrooms reflect a wide range of abilities among the "typical" students. Regardless of the reasons, teachers today find that the large-group "one-size-fits-all" lesson is not likely to be effective. When teachers incorporate into their lesson plans activities designed to meet varying needs, they ensure all students' access to the curriculum, so all students are able to respond and learn. This practice is commonly referred to as "differentiated instruction." This article discusses the lesson planning process using the principles of both differentiated instruction and universal design for learning.