Parasitic helminth infections are one of the most important causes of production loss in livestock worldwide. Grazing dairy cattle are exposed to various worm species, all of which can affect health, welfare and productivity to varying degrees. For several decades, helminth control relied primarily on the frequent use of broad spectrum anthelmintics; however, the use of such treatments needs to be moderated to avoid selection pressure for anthelmintic resistance. This chapter describes the likely helminth threats to grazing dairy cattle, with particular emphasis on the issue of anthelmintic resistance. It then offers a review of progress in developing evidence-based control programmes to reduce selection pressure for anthelmintic resistance. Finally, the chapter reviews progress in the development of anti-helminth vaccines. Such vaccines are a long way off commercial availability, but recent progress suggests that these could form part of a sustainable solution to helminth control on dairy farms.