The 30-year-old Nigerian woman went into labour 36,000 feet up, causing the pilot of the British Airways plane to divert to Palma de Mallorca, in the Balearic Islands.
The woman was 26 weeks into her pregnancy when she went into labour.
The woman gave birth in a flatbed the business class section of the plane. Once the plane had touched down, mother and baby were raced to hospital where they are said to be stable.
Under BA regulations, pregnant woman can fly on their planes until the end of their 36th week, or 32nd week if carrying more than one baby.
The plane, a Boeing 777 carrying 296 passengers, was en-route from Abuja, Nigeria to London when she went into labour.
Once the emergency was dealt with, the plane continued on to the UK, arriving two hours late.
A spokesman for British Airways said: ‘Our cabin crew, who are trained in birthing procedures, assisted with the delivery of a baby on board our flight from Abuja.
‘The Captain diverted the aircraft to Palma so that mum and baby could be taken to hospital.
‘We are in touch and will continue to provide any support and help we can.
‘We wish the mother and her little one all the very best.’