A spark plug (20) for igniting a mixture of fuel and air of an internal combustion engine comprises a center electrode (22) and a ground electrode (24). At least one of the electrodes (22, 24) includes a body portion (28, 30) formed of thermally conductive material and a firing tip (32, 34) disposed on the body portion (28, 30). The firing tip (32, 34) includes a ceramic material, providing an exposed firing surface (36, 38). The ceramic material is an electrically conductive, monolithic ceramic material. Examples of preferred ceramic materials include titanium diboride, silicon carbide, ternary carbide, and ternary nitride. The ceramic material can also include oxides, borides, nitrides, carbides, silicides, or MAX phases.