Has Derby County ever won a major European trophy?

No, Derby County has not won a major European trophy. The highest level of European football they have achieved is the 1973 UEFA Cup Winners' Cup final, where they were beaten by the Italian side Juventus.

Derby County have had some success in the English domestic competitions, having won the First Division twice, in 1972 and 1975, and the FA Cup in 1946. They have also achieved success in the League Cup, reaching the final in 1975 and 1976, but were beaten on both occasions.

Despite not having won a major European trophy, Derby County have had some memorable moments over the years, such as their run to the semi-finals of the European Cup in 1973 and their victory over Real Madrid in the 1974-75 UEFA Cup. They have also enjoyed success in the UEFA Cup Winners' Cup, reaching the semi-finals in 1972, 1974 and 1975.