Tijs Klaassen (1993) picked up the double bass at the age of 19 during his second year at the Conservatory of Amsterdam. Switching from bass guitar to completely focus on the instrument he loves the most. He studied at the faculty with jazz teachers Ernst Glerum, Frans van der Hoeven, Ruud Ouwehand and classical teacher Peter Leerdam. In the last four months of 2017 he studied with David Wong at the Boyer College of Music in Philadelphia. During his stay in the United States he took private lessons with Ron Carter, Orlando Le Fleming, Rick Rosato and Ben Street. He finished his master studies in 2018 magna cum laude.

Tijs won the Prinses Christina Concours in 2012 as a member of the group ‘Oosterdok 4’ and again in 2016 with the Ian Cleaver trio. As a member of the Mo van der Does quartet, he won the Expression Of Art Award in 2018.
As the leader of the Tijs Klaassen Quintet, he won the Keep an Eye the Records Award 2018. This will enable him to record his debut album featuring his own compositions which will be released next year.

With the Floris Kappeyne trio he played and toured in Tanzania, Slowakia, Belgium and Germany. Their debut album was released in june 2017 on Challenge Records International and features all original compositions by Floris and Tijs. In the same year, the trio appeared on Dutch and Belgian tv shows. In january 2019, the trio presented their second album Synesthesia at the great Bimhuis in Amsterdam.
Klaassen is the bassplayer of the Josse van der Schaft trio which released their debut album ‘Hollow’ in the beginning of 2018.
Since 2018, he is the regular bassplayer of the newly formed Peter Beets/Henk Meutgeert New Jazz Orchestra which made their debut on the 2018 Amersfoort Jazz Festival.
He will appear on the debut record Common Myths by Saxophone player Mo van der Does which will release later in 2019.
He also appears on three records released by trumpet player Gidon Nunes Vaz.

Playing with these groups, and as a sideman with others, led him to play at festivals and venues like: het Bimhuis, North Sea Jazz Festival, Muziekgebouw aan het Ij, het Concertgebouw, Goois jazz festival and jazzclub Mampf.

He has worked professionally with musicians such as Jasper Blom, Peter Beets, Martijn van Iterson, Henk Meutgeert, Yuri Honing and Theo Loevendie.