Teaching Leaders and the Future Leaders Trust, two charities that run leadership development training for teachers in challenging areas, are to merge.
James Toop, chief executive officer of Teaching Leaders, will become chief executive officer designate of the newly merged organisation.
He said that the current training programmes will continue to run.
"This is the right time for us to be taking this ambitious step," Mr Toop said. "The education landscape is changing fast and school leadership has diversified to include executive heads and academy trust CEOs.
"Headteachers and leaders looking for expert leadership development will now be able to deal with one organisation and we, in turn, will continue providing them with outstanding professional development.
"Our current programmes will continue as normal. We will bring together the expertise from both our organisations to develop enhanced programmes, which will equip school leaders in England’s challenging schools to transform educational outcomes for their pupils"
The charities have a joint network of more than 3,500 school leaders.
The Future Leaders Trust was set up in 2006 and its first headteacher was appointed in 2009. It delivers a range of programmes for senior leaders through to academy trust CEOs.
Teaching Leaders was set up in 2008. It was developed in partnership with Future Leaders, ARK, Teach First and the National College for Teaching and Leadership. The charity runs programmes specifically focused on developing outstanding middle leaders and supporting the transition from teaching to middle leadership.
Baroness Sally Morgan, chair designate of the new organisation, said: "Great leaders change lives and this is a decision that will enable both organisations to achieve our mission of ending educational disadvantage faster and more effectively."
Earlier this year, Heath Monk, former chief executive of The Future Leaders Trust, was appointed as executive director of the Schools of King Edward VI Foundation in Birmingham. Jacqueline Russell, the trust's deputy CEO, was appointed as acting CEO.