Relations between the North and South of Ireland were very strained with the enactment of the Republic of Ireland Act in Ireland in 1948 and the Government of Ireland Act in the UK in 1949. The increased tensions spilled out onto sport on many occasions throughout the 1950s with many fractious incidents caused by the political climate at the time. Issues arose over flags, anthems and other emblems; others arose over legacy issues relating to governance on an all-Ireland basis. The splits in soccer, athletics and cycling continued unabated in the 1950s. The Irish Football Association (IFA) and the Football Association of Ireland (FAI) could no longer select players born outside their jurisdiction from 1948 even though the last occasion the IFA selected players born in the Republic of Ireland was 1950. Both endured a particularly turbulent relationship in the 1950s. Sports such as rugby, hockey, bowls and golf also had to deal with controversial incidents relating to how they dealt with governing sport on an all-Ireland basis. This chapter examines the many incidents that occurred throughout the 1950s in sport, identifying the key factors of the political climate at the time that brought such issues to the fore.