Geological time is one of the most important notions of scientific thought, and is essential in decision making regarding socially-responsible natural resource utilization and environmental change, and is also fundamental to the comprehension of Evolution. Building this notion involved the acceptance of new ideas throughout Geology’s timeline, thus, we defend that its complexity is due to its historical development, in which several different fields of study needed to be brought together. This review work shows that some of the difficulties found in comprehending Geological Time in schools are: high degree of abstraction, interpretation of huge numbers, dimensions and events far removed from human experience, and religious conflicts that interfere with the acceptance of a very old Earth. Proposals to overcome these difficulties are: using analogies, working on activities involving a dynamic view of the planet and its geological processes, introducing the history of geosciences, and employing historical narratives. Thus, it is essential to develop investigations on the teaching of Geological Time in Brazil, and to carefully consider the training of teachers.Geological time is one of the most important notions of scientific thought, and is essential in decision making regarding socially-responsible natural resource utilization and environmental change, and is also fundamental to the comprehension of Evolution. Building this notion involved the acceptance of new ideas throughout Geology’s timeline, thus, we defend that its complexity is due to its historical development, in which several different fields of study needed to be brought together. This review work shows that some of the difficulties found in comprehending Geological Time in schools are: high degree of abstraction, interpretation of huge numbers, dimensions and events far removed from human experience, and religious conflicts that interfere with the acceptance of a very old Earth. Proposals to overcome these difficulties are: using analogies, working on activities involving a dynamic view of the planet and its geological processes, introducing the history of geosciences, and employing historical narratives. Thus, it is essential to develop investigations on the teaching of Geological Time in Brazil, and to carefully consider the training of teachers.