Mathematics curricula in the early years emphasize exploring patterns as an important stepping stone to algebraic thinking. Key expectations for young children are for them to recognize and describe visual patterns in the environment. When children are asked to identify patterns, what criteria do they apply to make a decision and on what do they base their descriptions? How is their decision making the same or different from early childhood educators? Using photographs, I investigated young children's and elementary educators' assumptions about the necessary criteria for identifying and describing patterned and nonpatterned images. Both students and teachers used repetition and predictability as their main criteria, but participants applied these criteria in a variety of sometimes contradictory ways. A number of issues arose regarding children's and teachers' perceptions of patterns that have implications for how patterning is addressed in the early years. (Contains 1 table and 1 figure.)