The ban comes after his red card in Ulster's Guinness PRO14 Round 2 fixture against Ospreys on October 10th.
He will miss the clash against Italy in Dublin on Saturday and the away game against France a week later.
Henderson was sent off for 'dangerous play in a ruck or maul', which is Law 9.20.
The lock's sending off was upheld at a disciplinary hearing today.
Henderson has the right to appeal and his suspension will expire at midnight on November 9th as things stand.