In this paper the doctrines on time of Plato, Aristotle and the Stoics are briefly presented. After a succinct introduction tending to show the relevance time has both for the common human awareness and for philosophers, the author focuses on the connections the creation of universe has with time in Plato’s definition of it as a “moving image of eternity” (such as it is presented in the Timaeus). The Aristotelian position of time is treated in the following part of the article. First, the author tries to show Aristotle’s challenges to Plato’s conception of time; second, he concentrates on Aristotle’s characterization of time as “a number of change in respect of before and after”, and the relation between movement and time. This section cocludes with a brief reference to Aristotle’s thesis that both time and movement are everlasting. Finally, the paper deals with the Stoic view on time: i.e. “the dimension of motion according to which measure of speed and slowness is spoken of”, pointing out that (i) time is an incorporeal -something which, albeit not existent, is subsistent; (ii) although the things truly existent (bodies) are the real causes, time -regarded as an incorporeal- plays a crucial role in the explanation of reality, because bodies and icorporeals, it is argued, are complementary terms. In addition to that, some connections with Aristotle are emphasized, too.