Summary: What is the role of patterns in developing algebraic reasoning? This important question deserves thoughtful attention. In response, this article examines some differing views of algebraic reasoning, discusses a controversy regarding patterns, and describes how three types of patterns‒in contextual problems, in growing geometric figures, and in repeating geometric figures‒have been used to develop teachers’ algebraic reasoning. (Contains 5 figures and 1 table.) (ERIC)