There is increasing interest in essential oils as plant protection agents because of their relative environmental safety. The biological activities of essential oils and/or their single pure compounds are manifold. They demonstrate efficiency against various organisms such as arthropods. In this review, general strategies for potential future applications of essential oils are described. The effect of selected monoterpenes (carvacrol, thymol, linalool, 4-terpineol), phenylpropanoids (eugenol, anethole) and salicylates (methyl salicylate, salicylaldehyde) on plant diseases, pests and beneficial arthropods are discussed. Thymol and carvacrol appear specifically effective in the suppression of pest reproduction. However, the relatively high costs in the use of essential oils such as the high volatility of the substances and their potential phytotoxic nature are problematic. Further research should involve investigations on appropriate formulations of products, effective blends of single compounds and on suitable dosages for efficient plant protection without phytotoxic side effects.