The 34-year-old was investigated by the Football Association on two separate occasions in relation to allegations made by former Lioness Eni Aluko.
The 30-year-old striker claimed that in 2015 Sampson asked mixed-race midfielder Drew Spence how many times she had been arrested, and in another incident in 2014, the football coach is alleged to have advised Aluko not to invite her family over from Nigeria due to concerns that they will bring the Ebola virus with them.
Spence has since backed up the allegations and revealed that she was not interviewed during the investigations by the FA, which cleared Sampson of any wrongdoing.
It has been widely reported that the English governing body will announce the manager's departure at a press conference this afternoon.
According to BBC Sport, Sampson's exit relates to newly-uncovered allegations about his behaviour in a previous role from a number of years ago.
The Welshman, who has led England Women to two successive semi-finals in major tournaments, has vehemently denied the allegations.