Weeds are among the major limiting factors in agricultural production, reducing crop growth and yield through competition with cultivated plants for water, light, nutrients, and space. Although the extensive use of synthetic herbicides is one of the most effective approaches to weed control, it is associated with several adverse consequences, including soil and water contamination, harm to non-target organisms, increased production costs, and, particularly, the emergence of herbicide-resistant weed populations. Therefore, environmentally friendly and alternative approaches to weed management have received increasing attention. Allelopathy is a natural mechanism of chemical interaction among plants, in which secondary metabolites, known as allelochemicals, are released by plants and can either stimulate or inhibit the germination and growth of neighboring plants, including weeds. These compounds enter the environment through root exudation, leaching from aerial plant parts, volatilization, and the decomposition of plant residues. Phenolic compounds, terpenoids, alkaloids, and certain flavonoids are among the major groups of compounds associated with allelopathic effects. Research evidence indicates that the use of allelopathic plants such as sorghum, rye, rice, sunflower, and Brassica species, as well as the application of plant residues, mulches, cover crops, crop rotation, intercropping, and aqueous extracts, can effectively reduce weed density and growth. Therefore, allelopathy can serve as an important component of integrated weed management by reducing reliance on synthetic herbicides and contributing to the development of sustainable agricultural systems.