In today's world of technological revolution, children need to be encouraged to be ready to acquire lifelong knowledge and skills in the 21st century. This paper presents an overview of the application of technologies in children's learning environment which apparently will give them the opportunity of making use of their thinking skills in order to develop socially and emotionally. The paper also looked into various ways of using these technologies in developing children's horizon, like using (CD-ROM story books and picture books, mobile and makerspace technologies). The paper examined the roles of librarians in meeting the needs of children in the application of technologies in promoting children's learning in the 21st century and challenges faced by librarians in meeting the demands of technology literacy development of children. Strategies on how to overcome these problems were provided. Recommendations that can help in promoting children's learning through technology were also provided.