Dr Elaine Storkey is moving on after 16 years as President of Tearfund.
The academic, theologian and preacher will stand down next month, having served in the role since 1997.
"In an era when the rich get richer, and the poor of the world face greater economic, social and ecological burdens it is more vital than ever that Christians work together for justice and sustainable development," she said.
"Tearfund strives to be faithful to its fundamental Christian vision and to work with partners across the globe to fight poverty and transform communities.
"My years as President have brought me in close contact with amazing people, whose consistent witness to Christ's redemptive love in the midst of hardship and disaster has made an enormous impact on my own life.
"Many of those relationships will go with me into the future, as I remain profoundly grateful for what they have taught me and for the deep privilege of serving them, through Tearfund."
Her contribution to the organisation will be celebrated next month at a reception in the House of Commons hosted by Stephen Timms MP.
"We are very grateful to Elaine for her service to Tearfund over many years," said Matthew Frost, Tearfund's Chief Executive.
"Elaine has given her time and expertise generously and tirelessly, representing Tearfund both the UK and overseas and has helped us to develop a better understanding of justice, particularly in the area of gender.
"We have valued Elaine's theological insight which has inspired many to a deeper understanding of God's call to each one of us. Her passion to speak out against injustice has inspired many in their own journeys of faith, and there are many among our staff, supporters and our global partners who have been helped immensely by her wisdom.
"We will of course stay in touch with Elaine, and we hope and pray that she continues to inspire others and to be blessed herself by her ministry."
A new President has not yet been appointed by Tearfund and the development agency continues to be represented publicly by its Vice-Presidents, who include former Archbishop of Canterbury Lord Carey, Alpha Course pioneer Nicky Gumbel, and Reheboth Foundation founder the Reverend Celia Apeagyei-Collins,