The goal of this experimental research was to demonstrate that creative thinking could be trained in primary school children. After asserting the difficulty to determine a unique definition of creativity – the concept fits to several fields and areas of interests – the capacity to produce numerous ideas and to think divergently was chosen as the framework within creativity as a way of thinking that can be assessed and measured. Even though creativity is challenging to define and consequently to operationalize, tests exist with the purpose to evaluate creativity levels in individuals. Starting from the Test of Child Creativity (TCI) an Italian mental reactive aimed at measuring the potential of creative thinking in individual children, a Group Creativity Assessment (gTCI) was made up with the objective to test 224 children belonging to 10 primary school classes (5 second grades and 5 third grades), achieving creativity scores of groups. The aim was to investigate whether children’s attitude to think divergently would improve after participating in a creativity training made up of 10 interactive one-hour long sessions. For that reason, all the sample of children were tested in T0 before the training; afterward 8 out of the 10 classes were weekly trained, before being all 10 classes tested again in T1, 10 weeks after T0. The hypothesis was that the trained classes would have improved in creative thinking, whereas the control groups would have not. It was therefore demonstrated the efficacy of the specific technique to train creative thinking that was conceived, developed and administered to the children.