For most business owners, your CPA is your primary trusted advisor when it comes to the financial success of your business. We treat all of our clients with personal service and expertise, building long-term, client-focused relationships.

Our goal is to provide quality accounting, auditing, tax preparation and business consulting for small to medium sized firms. We care about your success and take the time to know and understand your business and individual financial needs. Our depth of experience enables us to deliver personalized service to help you achieve your goals.

Why Work with Our CPA Firm?

We offer the breadth of services clients get with larger accounting firms but with more personal attention. What sets us apart is that we provide the most experienced team on every client account and we save our clients money.

When we ask our new and prospective clients, what do you pay your accountant for? The most common answers we received were: "To figure out my taxes for my business" or "So that my business stays compliant."

Although this may be the initial reason business owners hire a CPA, over time, hiring an accountant should contribute to your peace of mind. When you work with John Harmon, CPA, we get to know your business intimately so we can provide advise and support whenever you need it.

Working Ownership

John Harmon has 32 years of experience in accounting.  Many larger accounting firms reserve their managing partners for large companies, while giving the day-to-day work to junior accountants, or third-party vendors who work overseas. John insists on offering his high level of expertise to every one of his clients. The result is more a thorough, accurate, higher quality end product.

Also key is John's practical business knowledge formed in working from a young age in a successful family business that grew to 100 employees.

About John Harmon

John Harmon, CPA - Marlborough, MA

John Harmon is your trusted advisor for personal and business financial needs.

Client Testimonials

John Harmon has helped me both personally and professionally with multiple business, including one that needed a significant degree of restructuring. His work, advice, answers and approach are all detailed, thorough and completely … Read more »

David Foster, Principal
Foster and Wilson (Klokov Equipment)


We have worked with clients across a wide range of industries throughout the US. We take the time to understand your individual situation and industry and then apply our knowledge of changing tax laws to help you make the best business and personal decisions.

We constantly monitor tax legislation, regulations and court rulings so we provide you with the most effective tax planning to ensure the future success of your business and personal finances. We customize our solutions to the you and your business.

We have provided specialized services and expertise to clients in many industries including but not limited to:

  • Professional Services - Medical practices, engineers, consulting firms and other professional services firms.
  • Consumer Services - Construction, trades, automotive, health & wellness.
  • Retail - In addition to servicing many dozens of retail operations as a CPA, John Harmon grew up in a family business of 9 retail stores, light manufacturing and a regional distribution company. We provide a wide variety of accounting and financial management services for specialty retailers.
  • Restaurants - Private restaurateurs face a number of special challenges. The business model incorporates manufacturing and retail distribution under one roof. Our largest restaurant client now operates 13 locations in 2 states.
  • Engineering Services - While you are designing tomorrow's products and working/living spaces, we’ll support that by simplifying your bookkeeping and tax challenges. One often overlooked area are specialty tax credits. If you have income from several sources, states, or countries, that’s not a problem. We serve international clients as far away as Indonesia and China.
  • Manufacturing and Supply Chain - We have decades of manufacturing experience, including inventory process flow design and improvement.

Contact us to learn more about how to build and apply a more efficient solution to your accounting and tax needs.