The plica is a remnant of the synovial folds during the coalescence of three compartments of the knee at 8 weeks of fetal development. The plica are classified according to their corresponding anatomic sites of the knee, such as suprapatellar, medial patellar, infrapatellar and lateral patellar plica. The medial patellar plica is considered to be the one most likely to cause problems and has been well documented in the literature. However, there are very few reports of problems being caused by lateral plica. We encountered one case of pathologic lateral plica that was excised by arthroscopy. We report this case with a review of the relevant literature.