The Richmond MP believes it is “wrong for people to try and come at my wife” after questions were raised over her stake in Infosys, a company founded by her father and which is still operating in Russia.
Mr Sunak said he has “enormous pride and admiration” for his father-in-law, as he described the comments as “very upsetting”.
He joked to the BBC’s Newscast: “Someone said, ‘Joe Root, Will Smith, and me – not the best of weekends for any of us’.
“But I feel, on reflection, both Will Smith and me having our wives attacked – at least I didn’t get up and slap anybody, which is good.”
Oscar winner Mr Smith slapped the awards’ host Chris Rock earlier this week, after a joke was made about his wife, Jada Pinkett Smith’s, appearance.
Mr Sunak went on: “You know, I think it’s totally fine for people to take shots at me. It’s fair game. I’m the one sitting here and that’s what I signed up for.
“Actually, it’s very upsetting and, I think, wrong for people to try and come at my wife, and you know, beyond that actually, with regard to my father-in-law, for whom I have nothing but enormous pride and admiration for everything that he’s achieved, and no amount of attempted smearing is going to make me change that because he’s wonderful and has achieved a huge amount, as I said, I’m enormously proud of him.”