There is a paucity of evidence regarding whether the effective outcomes of arthrocentesis in the management of temporomandibular joint disorders (TMJD) result from its use as a single treatment or in association with adjunctive therapy. The study aimed to compare arthrocentesis alone (ACA) and arthrocentesis (AC) associated with adjunctive therapy (AAAT) to determine the most effective treatment strategy. A systematic review was conducted in September 2023 using PubMed/MEDLINE, Scopus, Web of Science, and the Cochrane Oral Health database. Outcomes assessed included pain, maximal interincisal opening (MIO)/maximum mouth opening (MMO), and joint sounds. A total of 28 studies comprising 1,216 patients treated with ACA or AAAT were included. Across these studies, 31 temporomandibular disorder diagnoses were reported, with temporomandibular joint osteoarthritis (TMJ-OA) being the most common (32.3%), followed by temporomandibular joint internal derangement (TMJ-ID) (19.4%) and disc displacement without reduction (DDwoR) (12.9%). Comparisons showed no significant differences between ACA and arthrocentesis combined with hyaluronic acid (AC + HA) or corticosteroids (AC + CS) in most studies. Arthrocentesis combined with platelet-rich plasma (AC + PRP) was superior to ACA but generally less effective than arthrocentesis combined with PRP and HA (AC + PRP + HA). The benefit of adjunctive therapy after AC remains controversial; however, an additional effect of two different adjunctive modalities after AC seems evident.