The agency has picked up the joint brief following a four-way pitch and is charged with building awareness of Autoglass' offering across the fleet and insurance industries.
As well as handling corporate and b2b duties, the agency will work across consumer and digital comms.
H+K is also charged with reviewing Belron's comms and implementing best practice across its core markets.
The brief was formerly held by Lewis PR, which had worked with the glass specialist since January 2011.
The H+K team will be led by Ben Curson, group MD and leader of the agency's financial and professional services offering in the UK.
Curson commented: 'Autoglass is a very successful brand in the UK at an exciting stage in its development. We are pleased to be working with the senior team to build on this awareness, and communicate to a wider audience in support of the business needs.'
The agency will report to Samantha Day, PR manager for Autoglass, who joined the firm from easyJet in 2010 to step up its comms activities.
Day said: 'We look forward to developing relevant and impactful campaigns to further build on our industry-leading reputation.'
Autoglass is owned by South African glass replacement company Belron Group and services more than 1.5 million motorists a year.
Meanwhile, Hill+Knowlton last week retained its work to promote South Africa as a business and investment destination.
H+K's new three-year contract with Brand South Africa will see the agency support the country's international reputation, particularly focusing on Germany, UAE, Nigeria and Kenya, as well as the potential to expand the programme to Ghana, Zimbabwe and the Democratic Republic of Congo.