Speaking at the launch of the sponsorship, IRFU President Pat Fitzgerald said: "We are delighted to welcome Aon to the Irish rugby family and especially pleased that it is our Women's team that they have decided to put their support behind.
"Women's rugby has grown strongly and the success of our women in the RBS 6 Nations has been fantastic for the sport. Now, with a strong partner like Aon, we are confident the growth of our women's game will go from strength to strength."
Richard Endersen, Chief Executive Officer of Aon Ireland, said: "Aon has enjoyed a strong working relationship with the Irish Rugby Football Union for many years.
"That is why we are delighted and honoured to have been selected as the first ever sponsors of the Ireland Women's squad.
"Captain Fiona Coghlan and her team-mates have shown tremendous character and commitment over the last few years, culminating with their major success in 2013.
"We are confident that 2014 will be another successful season, and everyone at Aon Ireland is proud to support them as they begin their title defence.
"The word 'Aon' comes from the Irish word 'Uimhir a hAon' or number one. We are number one in our chosen business segments and we are pleased that we can support a team that, as Grand Slam champions, are number one in Europe."
Ireland Women's captain Fiona Coghlan said: "It is fantastic that Aon have given their backing to the women's game as it is a real recognition of the hard work that everyone involved in the game has put in over the year, which ultimately resulted in our Six Nations win last year.
"As we head into the defence of our RBS 6 Nations Championship, we are very proud to have such a strong partner on our Irish jersey."