The airline currently operates 16 flights a week between the two cities, twice daily five days a week and triple daily on Mondays and Saturdays.
From September 18, Qatar will add extra daily flights on Tuesday and Thursdays.
And from May 22, 2019, Wednesdays, Fridays and Sundays will gain third departures.
Via Doha, the airline connects Manchester to more than 150 destinations.
Ishfaq Jalal, Qatar Airways acting senior vice president Europe, said both tourist and business travel demand was driving its expansion of the route.
Qatar’s Manchester-Doha service will be operated using Boeing 787 Dreamliner and Airbus A350 aircraft.