Ms Lennon, who has been CEO since 2016, said that her decision to leave the business was simply a matter of timing.
“I have been involved in developing a new strategy for the business and believe the company is well set for the next stage of its development,” Ms Lennon said.
“The owners plan to invest in the business based on this new strategy and I feel that this is the right time for me to hand over the reins.”
Ms Lennon will remain in her position to help manage the transition process.
Enda O’Coineen of Kilcullen Kapital, which last year acquired Post Publications, said she had been a “tremendous” CEO.
“She oversaw the company’s return to profitability last year. She was instrumental in the successful sale of the business in 2018 and she played a key role working with us to bed down that acquisition over the last number of months,” Mr O’Coineen added.