The co-leaders of the Social Democrats, Catherine Murphy and Róisín Shortall, say they'll withdraw from the MacGill Summer School due to gender-imbalance on panels.
They're calling for significant changes to be made across all sessions.
The deputies accepted a place to speak on panels, but say they were not aware the programme for other sessions was predominantly male.
Of 56 speakers listed to talk, 12 of them are women - including Deputies Murphy and Shortall.
Both leaders say they were "surprised" by the organisers claim that it was hard to find people with the right aptitude.
The assertion from @MacGillSummerSc that it's difficult to find people with the right aptitude is offensive to women says @CathMurphyTD - who has been invited to discuss dysfunctionality in Ireland - women must be part of discussions and solutions #MacGill2018 #NoCountryForWomen pic.twitter.com/cNtqlO6QCK
— Social Democrats (@SocDems) June 20, 2018
Deputy Murphy says: "I find the comment from the organisers about it being 'difficult to find people with the right aptitude' quite offensive when the implication is obviously that that is the reason more women are not invited to speak at the event.
"That is simply not true or else the organisers have conducted a very limited search.
"I cannot in good conscience take part in an event that has so blatantly disregarded the importance of equal female participation and for that reason I will withdraw from the session I was due to speak at unless significant changes are made across the programme."
Deputy Shortall adds: "Irish politics has come a long way from the male pale and stale boys club that it traditionally was. High-profile events like MacGill have a responsibility to reflect that change but also to recognise the wealth of fantastic and informed female voices across the Irish public life."