Tobias Ellwood said on Wednesday it had been a “huge privilege” to serve as chairman of the defence select committee but that he would be stepping down.
He confirmed he was stepping down in a tweet on Wednesday.
“It’s been a true honour to serve,” he wrote on X, formerly known as Twitter.
“I stand up, speak my mind, try to see the bigger picture and offer solutions, especially on the international stage, as our world turns a dangerous corner,” he wrote in his letter of resignation.
“I don't always get it right – so it's right I put my hand up when I don't. Poor communications, during the summer, in calling for greater international engagement in Afghanistan was understandably criticised at the time and reflected poorly on the committee.
“Whilst I do believe I retained the support of the majority of the committee, its dynamic and effectiveness would simply not be the same, and prove a distraction, if all in the room were not supportive of the chair.”
Pressure mounted on Mr Ellwood after he said he had “witnessed unreported compromises the war-exhausted nation is currently willing to accept” while on a trip to Afghanistan.
Originally writing in The Telegraph, Mr Ellwood has denied being a “Taliban appeaser” and said his brother was killed by Islamist extremists 20 years ago.
A subsequent apology failed to stop members of the cross-party committee from seeking to remove him from the high-profile role, with a no-confidence motion submitted on July 19.
Fellow Tory MPs Mark Francois and Richard Drax joined Labour's Kevan Jones and Derek Twigg in submitting the motion.
A notice period of 10 sitting days for such confidence motions had been due to expire on Thursday and Mr Ellwood's chairmanship had been expected to come under pressure.