The aim of the paper is to answer to the following question: was Plato a plagiarist of the Pythagoreans? The suspicion arises from an old tradition according to which Plato is accused of having plagiarized a supposed work currently lost of Philolaus of Croton. The Timaeus was taken as object of analysis in order to verify the existence of passages that could suggest this kind of activity. To this purpose, it was done a mapping of the main “Pythagorean” theories identifiable in the Timaeus, based on a review of the history of critical thinking. It was concluded that, undeniably, there is an explicit reference to the Pythagoreanism in the platonic work, which, however, does not constitute plagiarism, but rather can be better be understood as a Pythagorean influence, since Plato ends up transposing “Pythagorean” theories – as well as those of other Presocratic philosophers – for his own philosophical purposes.