The term allelopathy was introduced in the early 1990s. It originates from two Greek words: “allelon,” meaning “of each other” and “pathos,” meaning “to suffer or mutual harm.” Lately, the activity has been well known for its adverse effects on neighboring plants, leading to their death. It was considered that it occurs as a defensive response to a threat, but using this mechanism for weed management was not known. In past years, allelopathic activity in plants caught the attention of plant researchers, who used allelopathic plant interactions for weed management and the development of bioherbicides to address the harmful impacts of synthetic chemical herbicides. The chapter explores various types of allelopathic plant interactions, including weed-weed, crop-weed, and medicinal and aromatic plant-weed interactions, which can help in weed management and the development of bioherbicides. Although it is a safer alternative, much more research is needed in the field to develop a sustainable, environmentally friendly, and cost-effective bioherbicide.