Self-lubricating ceramic materials are mainly achieved through the addition of lubrication phases. Although incorporating lubrication phases can improve their tribological performances, the mechanical properties are consistently compromised. Thus, designing and fabricating single-phase ceramic with favorable self-lubricity is the relentless pursuit of researchers. In this study, the single-phase high-entropy ceramic of (Hf0.2Mo0.2Nb0.2Ta0.2Ti0.2)C exhibits self-lubricating properties and which closely relates to the testing condition. The wear rate and friction coefficient decrease with the increasing of loads (not above 30 N). And the friction coefficient of (Hf0.2Mo0.2Nb0.2Ta0.2Ti0.2)C samples against Si3N4 balls is as low as 0.3 under 30 N and 5 Hz. This originates from the carbon-rich tribo-film with self-lubricity, which is generated through diffusion and enrichment under the effect of tribo-induced. Single-phase self-lubricating ceramics—using own constituent elements to form a lubricating tribo-film—are expected to open up a new research field on the high-performance friction materials.