There are a variety of technologies that are increasingly being integrated into mathematics classrooms for their potential to increase student engagement, motivation, understanding, and achievement. YouTube can be an especially useful technology for students to create, share and interact with others, and learn more about mathematics. However, the most useful ways for YouTube to be used to improve the teaching of mathematics is a developing area that needs further research. The purpose of this paper is to describe how YouTube can be used with mathematical modelling activities to improve the teaching of mathematics by engaging students in realistic mathematical problem solving. (Contains 2 figures and 5 tables.)