Knowledge is gained in the process of learning and represents the level of awareness. The cognitive and informative level of knowledge about puberty includes the amount and quality of relevant information. During puberty, reproduction abilities are achieved. Puberty represents an essential hormone process accompanied by physical changes and rapidly transforming psyche, during which individuals become aware of their own personalities. Puberty is a significant element of sex education in the European as well as global dimension. Children need to be prepared for puberty in time and in an appropriate manner; this should include all related associations and contexts. Timely readiness for puberty means that children have the required knowledge before its onset - during pre-puberty when they are in primary school. The objective of the present research study is to identify and describe the level of knowledge about puberty among primary school pupils. We presented the partial results on the international conferences and in this journal we present an extended version of the outputs in the context of comparison the situation in the Czech Republic, China and Spain.