Marroco started working for the tobacco firm in Brazil in 1992 and was appointed to the board in 2019.
"Having been at the centre of the formulation of this strategy, I am convinced that this is the right strategic path for BAT," Marroco said in a statement.
The Brazilian, who has a degree in electrical engineering from the Universidade Federal do Rio de Janeiro, joined BAT's management board in 2014 as its business development director.
Prior to leading the company's transformation charge, Marroco - a keen follower of London's Arsenal soccer team and Formula One motor racing - headed its key Europe and North Africa regions.
BAT shares have risen about 8% since the start of 2019, but underperformed a 15% rise in the FTSE 100 over the same period.
'A Worthy Successor'
"We believe Tadeu Marroco is a worthy successor.. and we would not expect a broader shift in strategy as a result," JP Morgan analysts said.
Director Javed Iqbal will be interim finance director while the group looks for a permanent replacement for Marroco, the company said.
RBC analysts said the change of CEO was "unexpected", making them "wonder if BAT's performance might be faltering in a way that is not immediately apparent".