"While no formal decisions have been made about the role of Speaker should National win Government, I know my experience as Deputy Speaker this term will stand me in good stead."
Tolley was appointed Deputy Speaker in 2017.
She has been the MP for East Coast for the past 14 years.
"I worked hard to win the seat and I've loved every minute of representing such a diverse, hard-working, beautiful area," she said.
"I have no doubt National will find a strong candidate to take my place, and that person will have my full support."
Tolley's move is similar to Speaker Trevor Mallard's.
In the lead-up to the 2017 election, he opted for a Labour list placing over running for Wellington's Hutt South.