Twitter chief executive and co-founder Dick Costolo will step down from the role on July 1, but continue to serve on the board of directors.
The social media company's board has appointed Costolo's co-founder and current Twitter chairman Jack Dorsey as interim chief while it looks for a replacement.
Twitter's share price was trading 7.5 per cent higher in after-hours trading following the news. Investors have been left disappointed by missed revenue expectations in recent months.
The company is still to make a quarterly profit and has struggled to grow advertising revenue. According to eMarketer, Twitter grew its share of worldwide digital advertising revenue from 0.46 per cent to 0.87 per cent in 2014, as rival Facebook grew its share from 5.81 per cent to 7.93 per cent.
The former Google employee took over as Twitter chief in 2010 and oversaw the website's cautious IPO in 2013.
In a statement Costolo said:
I am tremendously proud of the Twitter team and all that the team has accomplished together during my six years with the company. We have great leaders who work well together and a clear strategy that informs our objectives and priorities. There is no one better than Jack Dorsey to lead Twitter during this transition.
He has a profound understanding of the product and Twitter's mission in the world as well as a great relationship with Twitter's leadership team.
As interim chief, Dorsey will continue to serve as chief executive of his payments and financial service company Square Inc. He commented: "Dick has put a world-class team in place and created a great foundation from which Twitter can continue to change the world and grow. We have an exciting lineup of products and initiatives coming to market, and I look forward to continuing to execute our strategy while helping facilitate a smooth transition as the Board conducts its search."