Context: Viscosupplementation is widely used for management of knee osteoarthritis. Many formulations of hyaluronic acid (HA) are available, ranging from a single injection to a series of up to 5 injections per treatment. Objective: To compare efficacy between single and multiple HA injection formulations. Data Sources: MEDLINE, EMBASE, Cochrane, Web of Science, Scopus databases were all searched. Study Selection: Full-text prospective randomized and nonrandomized controlled human trials, cohort studies, and cost-effectiveness evaluations in the English language comparing different injection regimens of viscosupplementation were included. Study Design: Systematic review. Level of Evidence: Level 1. Data Extraction: Data were collected using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Four databases were searched by a librarian and the principal investigator, identifying 6196 articles for screening. Results: Eleven studies met the inclusion criteria. Of the studies comparing single- with multiple-injection formulations of HA for treatment of knee osteoarthritis, there was no consistent difference in patient-reported outcomes. Furthermore, 5-injection formulations do not appear to be superior to 3-injection formulations. Conclusion: There are limited head-to-head trials comparing viscosupplementation formulations that differ based on number of injections, and in particular, there is a paucity of trials evaluating single-injection formulations. Based on the currently available data, there appears to be similar efficacy with the possibility for greater cost-effectiveness and less patient inconvenience with single-injection formulations.