The firms are working with rugby-based charity Touraid to bring under-14 rugby teams from the world's poorest countries to the UK later this month to play in a tournament with their more advantaged counterparts.
The players will be hosted by UK families in the hope of establishing long-lasting ties.
Ashurst is sponsoring a team from India; Clifford Chance a team from Rwanda; and Freshfields is bringing over a Kazakh team. For the majority of the boys, it will be the first time they have left their villages, let alone their countries.
In all, there are 10 overseas teams participating in the tournament, each with its own corporate sponsor.
The tournament was conceived around six months ago to coincide with the Rugby World Cup.
Ashurst project finance partner Nick Avery, who is also a Touraid trustee, said: "Rugby is just the catalyst. This is about facilitating friendships between boys from some pretty desperate situations and people in this country. If you have a friend in, say, Uganda, then you're more likely to look after that friend."
The hope is that host schools in the UK can create their own donations or even scholarships for their guest team-mates.
Ashurst was also instrumental in setting up Touraid as a charity a year ago. The firm stumped up an undisclosed sum as a start-up fund and provided pro bono tax, corporate, employment and real estate advice. It has since become Touraid's official corporate sponsor.
Touraid's chief executive Andy Berry said: "It's impossible to over-emphasise the desperate nature of the existence of some of the children who will take part in Touraid's Developing Nations Under 14 Cup.
"Support from these firms will provide the children with the essentials for the future: hope and encouragement that, in an often-difficult world, people do exist who will help you find your way."