The firm was founded in 1991 and has over 250 staff and £3.2bn in funds under management.
The table was compiled from results given by 231,000 employees to 70 questions on workplace culture.
These covered topics such as company leadership, personal wellbeing, career development and pay and benefits.
Some 88 per cent of staff at Brooks Macdonald said they were excited about where the company was going and 83 per cent felt their jobs were secure.
Some 93 per cent said they had a great deal of faith in chief executive Chris Macdonald.
Carey Shakespeare, head of marketing at Brooks Macdonald, said: "We are immensely proud of the accolade that has been awarded to us by the Sunday Times. We invest in our employee development and we work very hard to ensure that our staff feel valued.
"It’s extremely heartening that they view the company and its leadership so highly. This is a very proud moment in our history and it will motivate us further to ensure we live up to the expectations of our staff."
Second and third place in the table was insurer Admiral Group and financial management company Totemic.
Goldman Sachs was named best ‘big’ financial firm to work for followed by PricewaterhouseCoopers and RSA Insurance Group.
Jonathan Austin, chief executive and founder of Best Companies Ltd which conducted the research for the Sunday Times, said: "These awards highlight the achievements of organisations with good leadership and management which result in high levels of workplace engagement- factors that are even more important in difficult economic times.
"Companies that secured their place on the Sunday Times Best Companies to Work For lists are among the very best employers in the country and we congratulate them on their achievement."