The National Olympics Committee-Kenya (Nock) said Yego, who is the All-African Games champion, had been accepted by world athletics governing body IAAF to compete in London despite qualifying with a B standard.
"Kenya is classified as one of the countries that must qualify its athletes through category A in almost all disciplines and we do not enjoy the privilege of athletes representing this country under category B," Nock executive officer, Stephen arap Soi, told reporters in Nairobi.
"The only exception is Yego, who has been accepted by the IAAF because he is going to participate in javelin and that is the only category B."
Yego, who threw 79.95 metres last month to smash his national record of 78.34 metres set while winning gold at the continental games in Maputo last year, is overshadowed by the nation's distance runners.
"It will be a fantastic feeling to be in the Olympics. I will never forget the honour of being an Olympian but I'm aiming at throwing the A standard," said Yego, who works as a detective with the Kenyan police service and uses YouTube to improve his technique.
"It is hard to match what those people do since we are too far behind but competing against them will be enough for me," he added.
He is scheduled to travel to Finland this month for specialised training having achieved his career best after spending a month there.
The London Olympics runs from July 27 to August 12.