Children and adults wanting to fly the gadgets from November 30 will have to take the test to show they can do so “safely and legally”.
Those who fail or do not register as a drone operator by that date will face a fine of up £1,000 under new regulations from the Civil Aviation Authority (CAA).
The registration scheme opens on Tuesday and applies to anyone responsible for a drone or unmanned aircraft such as a model plane weighing at least 250g.
Registrants will be given a unique ID which must be displayed on their devices. The process will cost £9 and must be renewed each year.
From November 30 it will become mandatory for people to register as a drone operator and for them to pass a theory test.
The test will have 20 multiple choice questions, with applicants needing 16 correct answers to pass. It can be taken as many times as required.
Drone users must visit register-drones.caa.co.uk to access the new system.
Department store John Lewis stopped selling drones in May because of the chaos they are causing at airports.
Drone sightings at Gatwick in December last year caused around 1,000 flights to be cancelled or diverted over 36 hours, affecting more than 140,000 passengers in the run-up to Christmas.
A number of other airports have been forced to suspend flights for several hours due to drone activity this year, including Heathrow.
UK Airprox Board figures show there were 125 near-misses between drones and aircraft reported in 2018, up by more than a third from 93 the previous year.
In March, the drone no-fly zone around airports was extended from 1km (0.6 miles) to 5km (3.1 miles).
Dr Rob Hunter, head of flight safety at airline pilots’ union Balpa, said encouraging responsible drone use is “desperately needed to ensure a collision between an aircraft and a drone is avoided”.
He said: “We have been calling for drone registration for some time now as we believe that in the same way that other vehicles – be it those in the air or on the ground – are registered, so should drones.”
The CAA’s new platform will also be used to help return lost drones to their owners.
Anyone losing a drone is advised to post their details on the Drones Reunited platform, while anyone who finds one is encouraged to check if it has a registration number and enter the details online.
CAA assistant director of communications Jonathan Nicholson said: “The service is about giving something back to the community, helping responsible drone owners and operators to be reunited with lost drones and continue flying.
“Our aim is for the Drones Reunited platform to become an essential service for the drone community – the first port of call for anyone who has lost or found a drone.”