This article examines the factors that have contributed to the increased average height among Japanese people over the past century. It looks at historical context, genetics, diet and nutrition, exercise and activity levels, education levels and economic development as possible causes. The evidence presented suggests that all these factors have played a role in increasing heights among Japanese people. Genetics may be an important factor in determining individual height but environmental factors such as diet, nutrition, exercise, education levels and economic development are just as influential when it comes to increasing population heights.