We study a localization of functions defined on Vilenkin groups. To measure the localization, we introduce two uncertainty products UPλ and UPG that are similar to the Heisenberg uncertainty product. UPλ and UPG differ from each other by the metric used for the Vilenkin group G. We discuss analogs of a quantitative uncertainty principle. Representations for UPλ and UPG in terms of Walsh and Haar basis are given.