**Abstract**

Weed control through the use of conventional chemical compounds presented by synthetic herbicides is a widely used and successful method to control weed by reducing the negative impact of weed and increase agricultural production gradually. However, although the losses in agricultural production arising from weed competition are decreased through the use of synthetic herbicides, the negative impacts of these compounds on the environment and human health have raised awareness and created grave concern of a number of parties to safeguard the environment and humans. The adverse effect of synthetic herbicides can still occur even if such herbicides are applied at the recommended rates. Control weed naturally presented by allelochemical compounds provides an attractive, alternative and safe way to control weed synthetic herbicides. Previous works indicated that terpenoids as the most important group of allelochemicals have shown to exhibit a good phytotoxic effect against a wide range of weed species by suppressing germination and reducing growth. This review was a highlight to detect the desirable phytotoxic effects of some terpenoid compounds as a major content in essential oils on various weed species and the possible uses as natural weed killers.

**Keywords:** essential oils, terpenoids, allelochemicals, weeds, natural killers
