The objective of this study was to evaluate the effect of extracts obtained from leaves of Jatropha curcas L. on germination and initial growth of wheat. The aqueous and alcohol (ethanol and methanol) extracts of dried leaves were prepared in the concentration of 50 mg/mL. From the crude extract were made dilutions and obtained different concentrations. Some of the aqueous extracts tested were autoclaved. Over seven days, the germination characteristics and growth of wheat seedlings were evaluated with the different treatments. There was no effect of aqueous extracts on percentage of seed germination, however the methanolic and ethanolic extracts 5% affected the germination of a cultivar in study. There was a decrease in the germination speed index when the seeds were incubated with crude aqueous extract and methanol extract. The extracts affected the growth of seedlings and the most phytotoxic was the ethanol extract 5%. The autoclaved extracts promoted a reduction in all parameters evaluated. The results presented here show the extracts of dried leaves of jatropha promoted allelopathic effects on wheat.