The British broadband and mobile telecoms operator said on Monday that Jan du Plessis, who was appointed chairman in November 2017, had informed the board of his intention to retire once a successor has been appointed.
"The chairman throughout his tenure has demonstrated strong leadership ... been extremely supportive of management and any suggestion that he has impeded the transformation of BT is without foundation," BT said in a statement on Saturday.
"There has been no misalignment between the board and executive management over the company's strategy," BT added.
On Friday Sky News reported that Jansen, who joined BT as CEO in 2019, had told fellow directors he was frustrated with the speed at which it was taking key strategic decisions.
Jansen indicated that he was prepared to resign unless a new chairman who could accelerate the pace of change was appointed, Sky News said, citing several people close to the company.
Jansen is seeking to make the former monopoly more agile.
He wants BT to accelerate Britain's shift to fibre and 5G networks, and he is pushing the government and regulator Ofcom to create the conditions that would allow him to turn on the taps to billion of pounds of investment.
That aim was boosted by changes to corporation tax announced on Wednesday to incentivise investment.
Jansen said in November he was open-minded about selling a stake in the company's networks unit Openreach.
However, he said any decision would come after Ofcom publishes its new framework.
Du Plessis sought to build bridges with Ofcom during his tenure. "Above all, our relationship with Ofcom has improved significantly over the last three years," he said on Monday.
(Reporting by Paul Sandle; Editing by Alexander Smith and Ros Russell)