A Blue Badge, which can be used by people to park closer to amenities, costs £10 to apply for in England and must be renewed every three years.
The council revealed it had received almost 13,000 applications up to the beginning of last month.
Out of those, 8,593 were approved with 2,110 declined and more than 2,000 awaiting a decision.
The council said common reasons for refusals included insufficient supporting evidence, missed deadlines or applications not meeting the appropriate criteria.
An 88-year-old man told the LDRS he had been waiting almost three months after his original application was rejected, and had to go through the appeals process.
A woman from Daventry said she was left waiting three months for a replacement after submitting her badge for renewal and was left without the documentation for almost six weeks.