Wantage-based Tavistock Paper is a £7.3m-turnover, three staff company that is a wholly owned subsidiary of Portuguese paper distribution group, Inapa IPG.
Jonathan Addy, managing director of Gerald Judd Sales, said the acquisition would provide Tavistock customers and suppliers with a long-term sustainable partner.
Both companies will continue to trade independently, although buying and administration functions will be brought together. There will be a six- to 12-month transition period.
Addy said the two businesses had no overlap, and the acquisition would "provide ample opportunities for both companies to grow."
He said: "The acquisition is the result of several months of discussions between the owners of the two companies.
"Gerald Judd Sales have been strongly growing their business over the last two years. As an acquisition target Tavistock is a perfect commercial fit as it is profitable and there are no overlaps in customer base or supply."
He added that paper merchant mergers had been commonplace over recent years and this acquisition consolidated the UK industry a little further.
"Whilst Gerald Judd Sales is not actively seeking another acquisition at this time, we are in a strong financial position and would not rule out the possibility of further activity in the future."
Addy said no staff had been made redundant as a result of the acquisition.
Gerald Judd has 12 staff and turnover of £21.2m.