Wheat is a major food grain source of humans and genetic improvement has contributed significantly to its production. However, the genetic gain of wheat production has slowed in recent years due to its narrow genetic variability and draining of the gene pool in wheat breeding. This chapter elucidates both the contribution of wheat-related species to wheat improvement through alien introgression and breeding of synthetic wheat. The section on alien introgression from wheat-related species into wheat covers gene introgression from both annual and perennial wheat -related wild species as well as wheat-related crop species. This is followed by a comprehensive review of chromosome engineering technologies. The chapter concludes with a summary on the breeding of synthetic hexaploid wheat, and the issues of genome instability and homoeologous gene expression.