In recent years, our understanding of how tense systems vary across languages has been greatly advanced by formal semantic study of languages exhibiting fewer tense categories than the three commonly found in European languages. However, it has also often been reported that languages can sometimes distinguish more than three tenses. Such languages appear to have ‘graded tense’ systems, where the tense morphology serves to track how far into the past or future a reported event occurs. This paper presents a formal semantic analysis of the tense-aspect system of Gĩkũyũ (Kikuyu), a Northeastern Bantu language of Kenya. Like many languages of the Bantu family, Gĩkũyũ appears to exhibit a graded tense system, wherein four grades of past tense and three grades of future tense are distinguished. I argue that the prefixes traditionally labeled as ‘tenses’ in Gĩkũyũ exhibit important differences from (and similarities to) tenses in languages like English. Although, like tenses in English, these ‘temporal remoteness prefixes’ in Gĩkũyũ introduce presuppositions regarding a temporal parameter of the clause, in Gĩkũyũ these presuppositions concern the ‘event time’ of the clause directly, rather than the ‘topic time’. Consequently, the key difference between Gĩkũyũ and languages like English lies not in how many tenses are distinguished, but in whether tense-like features are able to modify other, lower verbal functional projections in the clause.