The 1978 Nations Cup, also known by its sponsored name Ambre Solaire Nations Cup, was a men's team tennis tournament played on outdoor clay courts. It was the second edition of the Nations Cup and the event was part of the 1978 Grand Prix circuit. It took place at the Rochusclub in Düsseldorf in West Germany from 8 May through 15 May 1978. Total prize money was £100,000 and in total 36,000 people attended the event.[1] The United States were the defending champions. Spain defeated Australia in the final, watched by a crowd of nearly 7,000, to win the title for the first time and earn the $60,000 first-prize money.[2][3]
The draw consisted of eight teams divided over two round-robin groups. The two best ranked teams from each group proceeded to the semifinals. Each match consisted of two singles and a doubles.