Mr McLaughlin, 70, was elected to the post in January.  He was the first member of Sinn Féin to take the post.
He made the announcement at the start of assembly business on Tuesday.
He said he wanted to be "doing some other things outside of this assembly".  Elections to the assembly are scheduled for next May.
"I know it is no secret to many members but I want to publicly put it on the record today that I will be stepping down as a member of this assembly at the end of this mandate," said Mr McLaughlin.
"I will not therefore be seeking re-election as speaker.
"I turned 70 during the Halloween recess and I look forward to the opportunity to be doing some other things.
"However, there will be plenty of time to be reflective at a later point and I am making this announcement at this stage only to show proper courtesy to the house. "
Mr McLaughlin, an assembly member for South Antrim, said there was a "lot of work" to do in the months ahead.
"There are a lot of issues I still want to try and make progress on with not much time to do it.
"However, I am particularly focused on managing the heavy legislative workload which I am expecting to confront us in the months ahead.
"That will be challenging and I will be speaking to the business committee about it."
Northern Ireland Assembly Speaker Mitchel McLaughlin has said he will not be seeking re-election at the next Stormont elections.