The 27-year-old -- whose career has been bedevilled by disciplinary issues -- was handed the suspension by an independent Rugby Football Union (RFU) disciplinary panel after being sent off at the weekend in his club Harlequins' 30-29 Premiership defeat by Sale.
Marler will definitely miss the games against Italy on February 4 in Rome and against Wales at Twickenham a week later -- the ban ends just four days before their third match against Scotland at Murrayfield.
"Joe Marler of Harlequins appeared before an independent disciplinary panel this evening after receiving a red card from referee Matt Carley during Saturday's Premiership match against Sale Sharks," read the RFU statement.
"He was sent off in the 58th minute for striking with the shoulder and making contact with Sale Sharks' TJ Ioane.
"Marler pleaded guilty to the charge and was suspended for a period of six weeks.
"He is available to play again on 20 February 2018."