This rapid review summarizes the latest primary research in temporomandibular joint (TMJ) injection treatment. The final literature searches were conducted on 4 January 2024. Selection was performed systematically following predefined eligibility criteria. Randomized control trials concerning the treatment of TMJ disorders with intra-articular injections were included. Studies on more invasive interventions were excluded. Quality of life, joint pain and range of mandibular mobility were assessed. Ultimately, 12 studies covering a total of 603 patients qualified. They concerned: (1) arthrocentesis (AC) and the administration of, (2) injectable platelet-rich fibrin (I-PRF), (3) platelet-rich plasma (PRP), (4) hyaluronic acid (HA), (5) non-steroidal anti-inflammatory drugs (NSAIDs), and (6) hypertonic dextrose (HD) with a local anesthetic. The dominant approach was to perform arthrocentesis before administering the appropriate injection substance (I-PRF, PRP, HA, or NSAID). Two current studies on the intra-articular administration of NSAIDs, specifically tenoxicam and piroxicam, are noteworthy. A mixture of PRP and HA was injected in another two trials. These two innovative approaches may prove to be significant directions for further research on injection treatment of TMJs.