The coefficient of friction of paper-based facing for a wet clutch was determined under a variety of sliding conditions. It is important to investigate the transitional friction characteristics of a clutch during the engagement and disengagement processes. An experimental apparatus was designed to obtain the friction characteristics for both constant and transient sliding velocity conditions. The latter condition simulates the locking-up and breaking-away processes of an automatic transmission. Experimental data obtained under stable sliding conditions were summarized on the Stribeck diagram. The data obtained under transient sliding processes were compared with stable sliding data. Friction characteristics related to the porous paper-based facing were discussed, taking into account the conventional concept of lubrication for ordinary metallic materials.