In this study, sepiolite as support material, was firstly used to synthesize a series of Co/xLa-SEP catalysts. Besides, a newly proposed biomass, poppy seed, was utilized in gasification for assessment of catalyst activity under various La loadings (0–10 wt% with a 2 wt% increment for each) and temperatures (550, 650, 750, 850 °C). The non-catalytic gasification resulted in the highest H2 concentration of 3.89 mol/kg poppy seed at 850 °C, whereas, the catalyst with 6 wt% La loading showed superior catalytic performance even at the much lower temperature of 650 °C, yielding 4.75 mol H2/kg poppy seed. Based on the results, char formation was almost utterly hindered in presence of 10 wt% La laoding at 850 °C, whereas a significant reduction of tar to 3.83 wt% was attained in corporation of 4 wt% La at 750 °C. The prepared catalysts were characterized by X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Fourier Transform Infrared Spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) and Scanning Electron Microscopy (SEM). SEM images and BET data presented that the Co/6La-SEP catalyst exhibited smallest particle size and the highest surface area (251.05 m2/g).