Allelopathy plays a major role in both natural and managed ecosystems regarding biodiversity and weed management in most countries. This chapter discusses the recent research on allelopathy carried out in Iran. Various research projects have been done in Iran in the last decades and reported in national and international journals. Iran has a long history in agriculture and so it is rich in indigenous knowledge on allelopathy. The review of recent publications showed that only in the last decade over 100 allelopathic species have been considered by Iranian researchers and as a matter of fact the most allelopathic investigations have been focused on economic crops and weed management.