The current ban was due to end on 25 May.
The firm said it had taken the decision because the UK government's advice not to travel to the resort  remained unchanged.
Flights were suspended in November 2015 after a Russian passenger plane crashed killing 224 people.
So-called Islamic State claimed responsibility for bombing the jet.
Thomas Cook had been selling holidays after 25 May, assuming that it would be able to fly to the region.
But it has confirmed that the advice from the Foreign & Commonwealth office (FCO) remains unchanged, and therefore it is extending its own ban.
The FCO advice is not to travel to Sharm el-Sheikh unless it is absolutely essential. That advice has implications not just for tour operators but for travel insurance too.
Thomas Cook said that as there was "no clear indication as to when the FCO travel advice may change",  it had taken the decision to cancel all bookings to Sharm el Sheikh up to and including Monday 31 October 2016.
A spokesman for the company said customers who have booked to travel to the region can either cancel or book alternative holidays.
Travel firm Thomas Cook has extended its suspension of bookings to the Egyptian holiday resort of Sharm el-Sheikh until November 2016.