Mr Sunak told journalists during his first official visit since entering Number 10 that he would instead be focusing on “the depressing domestic challenges” facing the UK.
A spokesman for the Scottish Government said the First Minister would head to Sharm El-Sheikh next month for the climate conference.
Ms Sturgeon was a fixture of COP26 in Glasgow last year, meeting with world leaders and climate activists.
The spokesman said: “Given the vital importance of governments working together to tackle climate change, it is the First Minister’s intention to attend COP27.
“Details of the ministerial programme are currently being finalised.”
Speaking to journalists during a visit to a south London hospital on Friday, Mr Sunak said: “The leadership that we have shown on the climate is unmatched … it’s important to me that, as Prime Minister, we leave behind an environment that is better for our children and grandchildren. I’m very passionate about that. I’m very personally committed to it.
“I just think, at the moment, it’s right that I’m also focusing on the depressing domestic challenges we have with the economy.
“I think that’s what people watching would reasonably expect me to be doing as well.”
The confirmation comes after the King, who has been an outspoken advocate of action to tackle climate change, has also said he will not go to COP27, with Downing Street arguing it was not the “right occasion” for the trip.
The UK Government’s environmental credentials were also being questioned after admitting it would miss the deadline to set flagship targets on cleaning up Britain’s waters and boosting biodiversity.
Conservative former culture secretary Nadine Dorries said Mr Sunak was “wrong” not to attend the Sharm El-Sheikh summit, saying global heating was the “biggest crisis facing our planet”.
Environment secretary Therese Coffey sought to defend Mr Sunak by arguing he would show “global leadership” rather than attending “just a gathering of people in Egypt”.
Ms Coffey suggested the conference was not one of the “big political summits” despite US president Joe Biden being expected to attend.
She insisted the “big political” iterations of the summits only take place every five years, with next month’s being more “low key”.
The UK hosted last year’s COP26 summit in Glasgow, with then-PM Boris Johnson stressing the need to act by warning it was a “one minute to midnight moment”.
The Washington Post has reported the US president will travel to COP27, in a boost for the gathering and its chances of securing action over the climate crisis.
But Ms Coffey, who was demoted from deputy prime minister to the environment brief this week, told Sky News: “The big push happened last year in Glasgow.”
Labour leader Sir Keir Starmer joined environmental campaigners in criticising Mr Sunak’s decision to miss the conference, saying: “If I was Prime Minister, I would be going. I would be convening and pulling people together and sorting out the issues that are confronting people. Talking to people this morning who can’t pay their energy bills, they expect their Prime Minister to be on the world stage sorting these problems out. It’s an absolute failure of leadership.”