He made the comment when asked about the policy of Wales boss Chris Coleman, who revealed earlier this week that his players' wives and girlfriends would be banned from the squad's base in France during the tournament as he attempts to remove all possible distractions.
And O'Neill batted the question away with a flippant comment, saying that only the "good-looking" wives and girlfriends would be allowed into the team hotel at the Euro 2016 finals.
Ireland number two Roy Keane had suggested earlier in the week that the Republic would adopt a relaxed approach, and O'Neill made his attempt at a joke when he was asked about the issue at his pre-match press conference on Thursday.
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"Well, it depends on how good looking the girls are," he said.
"If they are really attractive, they're very, very welcome. The uglier ones, I'm afraid not."
Keane had also commented that his family did not want to be anywhere near him when he was preparing for big games, and asked about that, O'Neill added: "Oh, I'm quite sure that's absolutely true."
Central defender John O'Shea, who sat alongside O'Neill during the press conference at the Aviva Stadium in Dublin, said his wife and family would be travelling to France to support him, but that their presence would not deflect him from his mission.
O'Shea said: "My wife and two kids will be coming over to support - if selected in the final squad - but it's one of those things. I'm experienced enough now to be focusing on the job at hand, which is getting out of the group."
O'Neill's comments were neither the funniest or the most sensitive discourse you will ever read on players' partners. However, this was clearly a joke - or at least an attempted one - rather than a genuine gaffe, and we hope it is treated as such. At the same time, let's also hope that O'Neill gets himself a new joke writer to bring his wisecracks out of the 1970s before his next press conference...
Additional reporting via PA
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