The certification of a boron carbide reference material for chemical composition is described. The mass fractions of 16 elements and two boron species are certified in an international interlaboratory comparison with 35 participating laboratories from six different countries. Beside chemical characterization the certification process includes homogeneity and stability testing of the candidate material boron carbide (type F360, 305M422). Details of the analytical methods used for chemical characterization and of the calculation of the uncertainties of the certified mass fractions are given. The new reference material ERM (R)-ED102 with certified mass fractions of 18 parameters (elements and species) and of the amount fraction of the isotope (10)B is a valuable tool for laboratories working in the field of advanced ceramic materials analysis to improve their analytical results.