Landsker Business Solutions, founded by Jeremy Bowen-Rees, has supported 2,500 Welsh businesses in key areas like HR, marketing, planning, and finance.
Over its 25-year span, Landsker has secured more than £150 million in funding and contributed to creating at least 6,000 jobs nationwide.
The company has also helped 750 start-ups in developing their brands.
This milestone will be celebrated with a black-tie event on September 5 at the Wolfscastle Country Hotel.
Guests will include clients, businesses, and stakeholders and entertainment will be provided by Juke Box Tonic.
An auction and raffle will benefit the DPJ Foundation, a charity providing mental health support to the Welsh farming community.
Limited tickets remain available.
