Ludwig van Beethoven's Opus 95, his String Quartet No. 11 in F minor, is his last before his exalted late string quartets. It is commonly referred to as the "Serioso," stemming from the direction for the third movement.

As is standard for string quartets, the piece is in four movements:

1. Allegro con brio
2. Allegretto ma non troppo
3. Allegro assai vivace ma serioso
4. Larghetto espressivo; Allegretto agitato; Allegro

It is one of the shortest and most compact of all the Beethoven quartets, and shares a tonality (F) with the first and last quartets Beethoven published (Opus 18, No. 1, and Opus 135). In character and key, as well as in the presence of a final frenetic section in the tonic major, it is related to another composition of Beethoven's middle period — the Overture to the incidental music he wrote for Goethe's drama Egmont.