It is widely accepted that there is no single test available which has the capacity to measure all aspects of balance performance. Many footwear intervention studies have used a package of balance assessment tools to explore the effects of shoes or insoles on postural stability. Similarly, there appears to be no single stability outcome measure that is sufficiently robust or sensitive to represent overall static or dynamic balance performance. This chapter provides an overview of postural stability assessment techniques and outcome measures commonly used in previous studies exploring the effects of footwear and shoe insole design on static or dynamic balance control; however, this list is not exhaustive. The chapter concludes presenting a selection of current literature reporting the effect of footwear interventions on postural stability in chronic conditions including Parkinson’s disease, multiple sclerosis, diabetes, and osteoarthritis. The summary is intended to highlight the relevance of postural stability assessment and footwear in clinical practice.