is a music cooperative specialising in contemporary music,  improvisation and musical education, established in 2013. Consisting of nineteen musicians, it is coordinated by a creative group  and specialises in contemporary music performance, improvisation, and artistic education.  

The ensemble performs regularly at new music festivals in Poland  and internationally, and its portfolio includes dozens of concerts  featuring both set repertoire and improvisation, chamber operas,  as well as seven studio albums, released under labels such as Kairos, DUX and Requiem Records. The ensemble actively cooperates with composers in Poland and abroad, and dedicates a significant part of its work to the artistic achievements of women. The ensemble’s concerts are set in clear, mostly extramusical  contexts. Narrative programming tends to involve audiences and  appeals to a wide range of listeners, rather than only to connoisseurs and music lovers. The search for new ways of presenting  modern music has brought the ensemble to many unusual venues  in which the concert situation is just as important as the artistic  interpretation of the repertoire itself.  

Since its inception, the ensemble has been involved in cultural  and artistic education, implementing original musical projects  for children and teenagers, providing courses and mentoring  programmes for outstanding performers, as well as presenting  music by the youngest generation of composers at national and  international competitions.  

With the support of Warsaw’s municipal authorities, in 2023  Hashtag Ensemble opened Poland’s first and only permanent  venue for new music: Hashtag Lab – Contemporary Music Space.  Housed in a modernist villa at 29 Barska Street, Warsaw, the Lab  presents concerts, spectacles, performances, music composition  workshops, educational programmes, exhibitions, and installations. It is a meeting place for artists and composers, a space for  debates, seminars, and conferences. In 2024 the ensemble was  awarded the Coryphaeus of Polish Music Event of the Year award  for the artistic events organised for its 10th anniversary. In 2025  it received the Society of Authors ZAiKS Award, followed by  the Polish Composers’ Union Award in 2026.

For many years Hashtag Ensemble has supported the integration of contemporary music circles by, among others, organising the #GrajFair campaign, sharing its experience of running  a cooperative and cultural institution based on democratic  principles with partners in Poland and other European countries. 

The creative group members establish cooperations with  new music ensembles abroad, take part in conferences, discussion panels, and social actions. Hashtag Ensemble also initiated  the Polish Guild of New Music, an association of the leading  modern music ensembles, producers, and festival curators.  The creative team leading the ensemble currently comprises Wojciech Błażejczyk, Aleksandra Demowska-Madejska, Lilianna Krych, and Marta Piórkowska. The ensemble is officially represented by the Sfera Harmonii Foundation. The Hashtag Ensemble is composed of Oliwier Andruszczenko,  Tymoteusz Bies, Wojciech Błażejczyk, Łucja Chyrzyńska, Aleksandra Demowska-Madejska, Adam Eljasiński, Marta Grzywacz,  Agnieszka Guz-Tarnowska, Paweł Janas, Ania Karpowicz, Magdalena Kordylasińska-Pękala, Krzysztof Kozłowski, Lilianna  Krych, Mateusz Loska, Maciej Nerkowski, Marta Piórkowska,  Dominik Płociński, Kamil Staniczek, and Kamila Wąsik-Janiak.