137 randomized controlled trials, consisting of 33,243 patients, were included in this network meta-analysis. The aim of this study was to assess and compare the efficacy of current pharmacologic treatments for primary knee osteoarthritis. Treatments such as intra-articular corticosteroids, intra-articular hyaluronic acid, acetaminophen, naproxen, ibuprofen, diclofenac, and celecoxib and oral and intra-articular placebos were compared based on their effect on pain, function, and stiffness. Results indicated that all interventions were significantly more favourable than oral placebo for pain outcomes. In addition, with the exception of intra-articular corticosteroids, all interventions were significantly superior to oral placebo with regards to functional outcomes. Naproxen, ibuprofen, diclofenac, and celecoxib were found to be superior treatments for knee stiffness, although most treatments led to similar effects.