All the organisations in the group will cease operations from today, including Thomas Cook Airlines.
Hundreds of retail shops will also be closed.
Despite agreement on a potential deal to save the company earlier this month, a last minute demand for up to £200 million in further liquidity pushed the tour operator over the edge.
Some 16,000 holidaymakers are booked to come back on Monday.
Authorities hope to get at least 14,000 of them home on chartered flights.
The government has chartered 45 jets to bring customers home and they will fly 64 routes today.
The size of the fleet will make it temporarily the fifth largest airline in the UK.
Operators including easyJet and Virgin have supplied some aircraft, with jets coming from as far afield as Malaysia.