Protein arginine methyltransferases (PRMTs) are a class of enzymes that mediate critical post-translational modifications through arginine methylation as epigenetic regulators. PRMTs have been shown to have a vast array of regulatory effects including in gene expression, signal transduction, and cellular proliferation. Dysregulation of PRMT activity has been seen in the progression of various cancers, including breast, lung, and colorectal cancer. Moreover, PRMT overexpression has been shown to correlate with poor patient prognosis. This review aims to explore the roles of the individual PRMTs in cancer and aims to highlight the latest and newest developments of PRMT inhibitors as emerging therapeutic strategies. Numerous preclinical and clinical studies have identified several novel compounds that effectively target PRMT activity and have shown significant therapeutic results. As such, this review aims to not only highlight the current research findings, but to also emphasize the significant need for future research on PRMTs as novel therapeutic targets in cancer.