The growth response of seedlings of Zea mays to aqueous extract of Lycopodium clavatum was assayed in the greenhouse using completely randomized design (CRD) with three replicates and five treatments. Seeds of Zea mays were grown in Petri dishes measuring 9cm wrapped with whatmam filter paper. The test treatments were aqueous extracts of L. clavatum leaves at different concentrations of 0%, 25%, 50%, 75% and 100%. Extracts showed both inhibitory and stimulatory effect on Zea mays seedling growth at different concentrations. The plumule length and radicle length were measured using a ruler. L. clavatum showed stimulatory effect at 25% concentration only and inhibitory effect at 50%, 75% and 100%. Radicle length decreased with increase in concentration with the highest length recorded in the 0% concentration (control) whereas the plumule length increased over the measurement period and also decreased with increase in concentration.