Mr Little only took up the role in June this year
The head of Twitter in Ireland has announced he is to leave the company.
Mark Little tweeted that he is departing "with heart full of gratitude & love for this team".
He says he has seen more change than expected at the company and "now it's time to move on".
In a statement, Mr Little said: "For several months, Twitter has been considering changes to its Media Partnerships team, which I led in Europe. In October, the decision was made to restructure the team and locate its leadership roles in the United States.
"I was asked to consider a possible return to the US, where I was living when I joined Twitter, or building on my role as Twitter’s managing director in Dublin.
"I decided that neither would be the right fit for me - or Twitter Dublin - and opted for a mutually agreed exit from the company."
Mr Little only took up the role in June, after the departure of its former CEO Stephen McIntyre.
Up to that point, Mr Little had held the role of vice president of media in Europe - having joined the company 12 months ago.
There has been no word yet on a replacement for him.
A Twitter spokesperson said: "Mark Little will step down in his dual role as MD of Twitter Dublin and vice president of media in Europe."
"We want to express our gratitude for his exemplary stewardship of Twitter Dublin and for leading our European Media team over the past 12 months."
Founder of social media news agency Storyful, Mr Little sold it to Rupert Murdoch's NewsCorp in December 2013 for €18m.