Building "happy schools" has been one of the key concerns by many countries in recent years with an aim to create a friendly, safe, and happy teaching and learning environment so that teachers and students can have more motivation in improving their teaching and learning achievements, thus bringing forth more happiness to the involved individuals and organizations. The article introduces the concept of a "happy school", outlined the perspectives on building happy schools by the world and Vietnamese political, cultural leaders, educational researchers as well as organizations so that they can be applied in the process of educational innovation. Thereby, the authors identify the key elements and criteria for such a "happy school" model, clarify the roles of the schools' headmasters as well as summarize a set of ten messages for a happy school to prepare under the current situation of school innovation.