The objective of this study was to evaluate the allelopathic potential of sunn hemp extracts on germination and initial development of maize. The trials were carried out in the laboratory and greenhouse with four concentrations (0; 7.5; 15 and 30%) of aqueous extracts obtained by grinding and leaching. In a germination chamber, more concentrated extracts (15% and 30%) inhibited maize germination, while shoot length (SL) was stimulated at 7.5% concentration. Ground extract stimulated root length (RL) at all tested concentrations. Root number (RN) was inhibited at higher concentrations of leached extract and stimulated for seeds exposed to sunn hemp ground extract. In the greenhouse, the longest root length (LRL) of maize was inhibited at the highest concentration (30%) of both extracts. The ground extract inhibited the LS in all concentrations and the 7.5% concentration stimulated the RN. It was concluded that sunn hemp extracts showed allelopathic effect on maize development, which varied according to how the extracts were obtained and concentrations used.