The Manchester practice is now a member of international group MGI Worldwide, which includes over 9,000 professionals in around 100 countries.
The network was established in 1947 and is now the oldest international accountancy group in the world. The annual revenues of all its members top £770m.
The accountancy firm said it made the decision to join following “increased demand” for its specialist UK tax and audit services for UK subsidiaries of overseas companies.
It said the move also comes in “readiness” for a “post-Brexit business landscape” in anticipation of new trade deals that would require international expertise.
Murray Patt, founder of Alexander Knight and Co, said: “Joining MGI Worldwide means we are part of a network of advisers who have expertise in all corners of the globe.
“As well as being able to access guidance from other member firms in their own jurisdiction, it means that we can secure referrals from international companies who are looking for specialist advice about setting up in the UK or who need specialist advice on the UK tax position.
Paul Winder, MGI regional co-ordinator for the UK and Ireland, said: “We are delighted to welcome Alexander Knight & Co into our international network.
“We have a high demand for UK expertise, particularly on tax issues and Alexander Knight & Co fits our key criteria of being highly skilled in this area. They also understand their clients’ businesses, aspirations and what it means to be entrepreneurial.”
He added: “We now have strong representation across every single continent in the world and a strong presence in every key economic centre throughout the world and Manchester and the North West is no exception to that.”