Polyphenols are an extensive group of secondary metabolites. Several studies have suggested that these natural plant compounds may help in the prevention and treatment of cancer. These metabolites present in fruits, vegetables, cereals, and other plant sources have demonstrated their potential to reduce cancer risk due to their antioxidant, anti-inflammatory, and antiproliferative properties. They can be obtained from plant sources using various conventional and environmentally friendly methods, often leading to higher yields. They can exert their anticancer potential through multiple molecular mechanisms, such as induction of apoptosis, inhibition of angiogenesis, and modulation of cell cycle progression. In addition, polyphenols have demonstrated efficacy in vitro, in vivo, and in silico models, with promising results in several types of cancer. Preclinical findings show potential, but further studies are needed to understand their clinical application fully, especially in refining doses and methods of polyphenol delivery for cancer treatment.