In an interview with US broadcaster ABC News, William said it was "very sad" that Diana, princess of Wales who died in a car crash in Paris in 1997, could not be there to see him tie the knot with his university sweetheart Kate Middleton.
His brother Prince Harry, who was William's best man for the ceremony at London's Westminster Abbey, said their mother probably had the "best seat in the house" at the service.
Asked if he missed his mother on his wedding day last April, William, 29, replied: "It was very difficult.
"I was sort of mentally prepared so I didn't want any wobbly lips or anything going on.
"It's the one time since she's died, where I've thought to myself it would be fantastic if she was here.
"And just how sad really for her, more than anything, not being able to see it. Because I think she would have loved the day and I think, hopefully, she'd be very proud of us both for the day.
"I'm just very sad that she's never going to get a chance to meet Kate."
William gave his bride-to-be the same sapphire and diamond engagement ring that his mother had.
The wedding ceremony was conducted a few steps from where Diana's coffin lay for her funeral.
Asked if it was difficult not having Diana with them, Harry replied: "Of course it was."
He added: "I think she had...the best seat in the house probably, but, yeah she would have loved to have been there."
Though Harry appeared at ease during the wedding, watched by billions around the world on television, he admitted to being "massively nervous".
"Everybody was nervous. And the whole thing was a bit of a blur to be honest, because, there was God knows how many millions or billions of eyes focused on us," the 27-year-old said.
Meanwhile on Tuesday, Queen Elizabeth II appointed William a knight of the Most Ancient and Most Noble Order of the Thistle, an order of chivalry dating back to 1687 that is the highest honour in Scotland.
Appointments to the order are entirely in the personal gift of the sovereign.
The monarch's husband Prince Philip, plus their two oldest children Prince Charles and Princess Anne, are already royal knights in the order, which has a complement of 16 non-royal knights.
They include George Robertson, the former defence secretary and NATO secretary general.
Besides being the Duke of Cambridge, his primary title, William is also the Earl of Strathearn in Scotland, near St Andrews where he and Catherine met.
William is already in the Order of the Garter, the equivalent in England, and wore the Garter star on his army uniform at his wedding.
