Serpentine Gallery director Julia Peyton-Jones, who launched the Serpentine Pavilion commission and turned the tiny London arts venue into one of the UK's most influential architecture clients, is to step down after 25 years.

Peyton-Jones – who instigated the pavilion programme that gave architects including Zaha Hadid, Peter Zumthor, SANAA and Frank Gehry their first opportunity to build in the UK – announced her impending departure today.

Peyton-Jones, 63, has been director of the gallery in Kensington Gardens since 1991. She will leave in July 2016, and the gallery has begun recruitment for her replacement.

"There is never a good time to leave an institution but I wanted to leave the Serpentine at a time of strength and success," she said in a statement.

"It has been a great honour to be director of the Serpentine through such an exciting period and to have worked with such incredible artists, staff and Trustees. In particular, I want to pay tribute to Hans Ulrich Obrist, our collaboration over the last 10 years to further develop the Serpentine's international reach across all its programmes and, to coin our phrase, 'to think the unthinkable', has been an incredible privilege."

Obrist joined the Serpentine Gallery as co-director of exhibitions and programmes and director of international projects in 2006.

In 2013, the duo oversaw the opening of the gallery's satellite venue – the Serpentine Sackler Gallery, which features a tent-like extension by Zaha Hadid.

The annual commission for the Serpentine Gallery pavilions has become one of the most anticipated events in the British architecture calendar since its launch in 2000.

The pavilions programme aims to give innovative architects their first opportunity to build a stand-alone structure in the UK. Subsequent pavilion architects have included Herzog & de Meuron, Toyo Ito, Daniel Libeskind, and Sou Fujimoto.

This year's pavilion was designed by Spanish architects SelgasCano, who created a colourful see-through plastic cocoon.

Dezeen is publishing a series of interviews with Peyton-Jones about each of the pavilion designs to mark the 15th anniversary of the programme.