Background: Cancer is an irregular proliferation of cells that starts with a gene mutation that alters cellular function, is triggered by several factors, and can be inherited or acquired. The aim of this review is to discuss the anticancer activity of basil and its components’ strength, focusing on its implication in cancer prevention and treatment. Methods: This systematic review involves all of the studies published from 1 January 2010 through 1 January 2022. Results: In this review, 16 research articles are included to discuss the potential anticancer ability of the extracts of various Ocimum basilicum varieties at various dosages, applied to different cancer cells. Of those 16 articles, 2 were in vivo studies, 13 were in vitro studies, and 1 study conducted both in vivo and in vitro experiments. Antioxidants and other bioactive compounds in basil leaves show important potential anticancer activity at dosage of 4 mg/mL as aqueous extract or essential oil up to 200 µg/mL could slow-down tumor growth and progression with regards to cell death and viability inhibition. At dosages from 50 to 500 µg/mL is effective as anti-proliferative activities. cytotoxicity, inducing apoptosis, slowing down tumor growth, and especially cell cycle arrest, both in vivo and in vitro. Human studies show effects at dosages from 1 to 2.5 mg/daily on general vital activities and on reducing cytokines activity. Conclusions: Based on 16 published studies, basil demonstrates important anticancer activities in vivo and vitro models, and it could act as a potential cancer.