Physical activity interventions among older adults vary widely in the techniques used to elicit behavior change. The purpose of this systematic review was to determine what behavior change techniques (BCTs) are used in interventions to increase physical activity among older adults using the theory of planned behavior and to make suggestions for BCTs that appear to be more effective. A database search identified peer-reviewed articles documenting interventions based on the theory of planned behavior. Seven articles (three randomized controlled trial, three quasi-experimental, and one n-of-1) from four countries (the United States, the United Kingdom, Australia, and the Netherlands) were included for review. Researchers independently coded BCTs using a hierarchical taxonomy of 93 BCTs. The most frequently coded BCTs included Goal Setting (n = 5 studies), Action Planning (n = 5 studies), and Credible Source (n = 5 studies). Of the 93 BCTs in the taxonomy, only 26 were used, indicating potential opportunities to implement and evaluate less commonly used techniques in future studies.