Yes, Arsenal FC has won an European tournament, the UEFA Cup Winners' Cup in the 1993-1994 season.

The UEFA Cup Winners' Cup was a competition that featured the winners of domestic cup competitions from different countries in Europe. Arsenal qualified for the tournament by winning the 1993 FA Cup, defeating Sheffield Wednesday 2-1 in the final.

In the tournament, Arsenal faced teams such as Standard Liege, Dinamo Moscow, and Parma in the final. The final was played at the Parken Stadium in Copenhagen, Denmark, on May 4, 1994, and Arsenal defeated Parma 1-0, with a goal from Alan Smith in the 21st minute.

This was Arsenal's second European trophy, as they had previously won the Inter-Cities Fairs Cup (now known as the UEFA Europa League) in 1970. The UEFA Cup Winners' Cup was discontinued after the 1998-1999 season, and Arsenal remains one of the few English clubs to have won the tournament.

References:

• "Arsenal FC - UEFA Cup Winners' Cup 1993/94." UEFA.com. Accessed September 8, 2021. https://www.uefa.com/uefacup-winnerscup/history/seasons/1993/.
• "1993-94: Arsenal end Cup Winners' Cup wait." UEFA.com. Accessed September 8, 2021. https://www.uefa.com/uefacup-winnerscup/news/0253-0d7e4d2f1d4e-1f2b8a5e9b8b-1000--1993-94-arsenal-end-cup-winners-cup-wait/.