Face of Nation : The four home nations agreed in October to allow a GB women’s team to try to reach Tokyo, but qualification depended on England’s success in France.
England beat Norway to reach the last four, while the USA beat France 2-1on Friday to ensure there are only three European teams in the semis.
There will be 12 teams at Tokyo 2020.
There was no agreement for a British men’s team in Japan – although they would have failed to qualify anyway.
Both sides took part in London 2012. A women’s team made their debut, with the men returning after 40 years away – with the home nations agreeing to that as a one-off for the home Olympics.
Both sides went out in the quarter-finals.
No combined British team featured at Rio 2016, with the associations of Northern Ireland, Scotland and Wales opposed to the idea.
Last June, England boss Phil Neville said fielding a Team GB team in Japan was “absolutely fundamental” for the growth of the women’s game – and said “it would be great if I could be a part of it”.
Unlike the men’s event – which is an under-23 tournament – the Olympics is one of women’s football’s biggest events, with no age restrictions.
The teams guaranteed a place are Great Britain, hosts Japan, Copa America winners Brazil and Oceania champions New Zealand.
The winners of the other World Cup quarter-finals – Italy v Netherlands and Germany v Sweden – will also qualify.
The other spots will be filled by two qualifiers from each of Asia and the North, Central American and Caribbean group, as well as one from Africa and the winner of a play-off between Chile and an African team.
The four semi-finalists from the men’s European Under-21 Championship – Germany, Romania, Spain and France – have qualified for Tokyo 2020.
Britain would not have been eligible even if England – who went out in the group stages – had reached that round.