He said that he 'deeply regrets' the tone and language used in some of his tweets
Barry Walsh has resigned from Fine Gael's Executive Council, the party has confirmed.
The resignation takes effect immediately.
It comes after it emerged that Mr Walsh had sent tweets to female politicians, including those in his own party, using words such as 'bitch.'
He also labelled Sabina Higgins a 'vile woman'.
Fine Gael Dublin Bay South TD Kate O'Connell circulated screen-grabs of tweets at a meeting of TDs and Senators on Wednesday night.
The controversy had prompted high-ranking party figures, including Taoiseach Leo Varadkar, to call for Mr Walsh's resignation.
In his resignation letter, Mr Walsh wrote: "I am doing so out of respect for the membership of the Fine Gael party, and for the Taoiseach in particular, in order to prevent any further distraction in relation to this issue.
"I also do so in the hope that it may bring an end to the 'trial by media' which has occurred in the last 48 hours and placed intolerable pressure on my family and friends."
He added that he 'deeply regrets' the tone and language used in some of his tweets, and apologised unreservedly for the "serious offence" caused.
He added: "I first got involved in politics because I have passionate views on many issues and have always enjoyed robust political debate, however I accept that with many of these tweets I took the political jousting a step too far.
"I look forward to this matter being considered by the Fine Gael Executive Council at its earliest convenience, and I am resigning without prejudice to any disciplinary investigation which may be undertaken by the party in relation to this matter."
The party's council chairman Gerry O’Connell confirmed he had received and accepted the resignation, noting the party will not be commenting any further at this time.