Background: Art-based interventions, including music therapy, are increasingly used in palliative care to support symptom management and improve quality of life in patients with advanced cancer. This systematic review and meta-analysis aimed to evaluate their efficacy in adults with advanced cancer receiving palliative care. Methods: The review protocol was registered in PROSPERO (CRD42025636049). A systematic search of PubMed, MEDLINE (Ovid), and Embase was conducted from database inception to 17 December 2024 (PubMed), 21 December 2024 (MEDLINE (Ovid)), and 10 January 2025 (Embase), and was updated in February 2026. Additional searches were conducted in ClinicalTrials.gov, WHO ICTRP, Cochrane CENTRAL, and Google Scholar in August 2026. Studies comparing art-based interventions with standard care or active control interventions were included. Risk of bias was assessed using the Cochrane RoB 2 tool, and certainty of evidence using the GRADE approach. Results: Eleven reports with 9 RCTs (involving 675 patients) met the inclusion criteria, all evaluating music-based interventions. Music-based interventions in addition to routine palliative care were associated with a statistically significant reduction in pain intensity compared with control conditions (SMD = −0.51; 95%CI: −0.98 to −0.03; p = 0.04; k = 3; n =224), although high between-study heterogeneity was observed (I² = 67.69%). They were also associated with higher quality-of-life scores (SMD = 0.92; 95%CI: 0.59 to 1.24; p < 0.0001; k = 2; n = 168; I² = 0%); however, the certainty of evidence was very low, making this effect highly uncertain. Conclusions: Evidence for music-based interventions remains very uncertain, precluding firm conclusions regarding clinical benefit. Further high-quality trials, including other forms of art-based interventions, are needed.