Liverpool-based Arena Housing Group has awarded the social housing team at the law firm a place on its new legal panel.
Weightmans LLP will advise the group on housing management and employment issues in relation to 14,000 property units in Merseyside, Manchester, Leeds and the Wirral.
The appointment comes just a few months after Weightmans won a two year contract with City West Housing Trust and a six year contract with Guinness Northern Counties.
Sian Evans, head of the social housing team, who led the tender process, said: "Arena is one of the largest providers of social housing across the North and their requirements sit very well with our core capabilities, so this is a really positive result.
"At a time when the Localism Bill and the concept of the Big Society look set to change how organisations such as housing associations operate, careful consideration needs to be given to how they will utilise the freedom afforded to them to get the best possible deal for their tenants and the communities in which they operate."
Following the firm's merger with Mace & Jones in May, Weightmans' enhanced social housing offering encompasses housing management, property, employment, procurement and governance and housing finance expertise.