Phenolic compounds are some of the most widespread molecules among plant secondary metabolites, which are of great significance in plant metabolism. With an objective to study the impact of some of these compounds on the seed germination and seedling growth, the seeds of cucumber (Cucumis sativus L.) were treated with distilled water (control), 5×10–5 M, 10-4 M, 5×10–4 M or 10–3 M, each of catechol, gallic acid or pyrogallic acid. Treatment of the seeds with the phenolic compounds significantly decreased the germination percentage, growth of radicle and hypocotyls and the fresh and dry weight of the seedlings. Out of the different concentrations of these compounds used, 10–3M caused the maximum inhibition. Among the phenolics used, pyrogallic acid was the inhibitoriest. However, total phenolic content in the seedlings increased in response to different treatments, in a concentration dependent manner.