About John P. Mullen Law Office

John P. Mullen Law Office is a solo commercial litigation practice based in Mississauga, Ontario. The office is run by lawyer John Mullen, who was called to the Ontario Bar in 1978 after earning a B.A. from York University and an LL.B. from Osgoode Hall Law School. The practice concentrates on construction, commercial, employment, estate, and real estate litigation, acting for clients that range from sole proprietors and family owned businesses to financial institutions and multinational corporations.

On the construction side, the firm has represented suppliers, equipment rental companies, subcontractors, general contractors, owners, and lenders in disputes over liens and contract claims. Its commercial litigation work has included shareholder, franchise, and partnership disputes, along with cases interpreting commercial leases and agreements for the purchase and sale of property. In employment matters the firm acts for both employers and employees on wrongful dismissal claims and disputes over non-competition and non-solicitation clauses, and its estate litigation practice covers contested wills, the interpretation of wills and trusts, and questions of mental incapacity or undue influence.

Mullen has also instructed on business law at Sheridan College and at Wilfrid Laurier University, and has taught bar admission and continuing education courses for the Law Society of Upper Canada.

Milestones & recognition

  • Called to the Ontario Bar in 1978.
  • Holds a B.A. from York University and an LL.B. from Osgoode Hall Law School.
  • Has instructed on business law at Sheridan College and at Wilfrid Laurier University.
  • Has taught bar admission and continuing education courses for the Law Society of Upper Canada.
  • A member of the Advocates Society, the Peel Law Association, and the Medico-Legal Society of Toronto.

In the community

  • Served as Past President of the Rotary Club of Brampton.

Good to know

A person using a wheelchairWheelchair accessibleA calendar with a checkmark beside a clockBy appointment

The neighbourhood

John P. Mullen Law Office works out of a suite at 106-218 Export Boulevard in Mississauga. The office serves businesses, financial institutions, and property owners in connection with the firm's construction, commercial, and real estate litigation practice.

Frequently asked questions

What areas of law does John P. Mullen Law Office handle?
John P. Mullen Law Office concentrates on construction, commercial, employment, estate, and real estate litigation. The practice represents clients ranging from sole proprietors to financial institutions and multinational corporations in contested legal matters.
I think I was wrongfully dismissed. Can the firm review my severance package?
John P. Mullen Law Office reviews severance packages and represents both employers and employees in wrongful dismissal disputes, including cases involving non-competition and non-solicitation clauses.
Can John P. Mullen Law Office help with a contested will or estate dispute?
John P. Mullen Law Office handles estate litigation, including contested wills, questions about the interpretation and enforceability of wills and trusts, and disputes involving mental incapacity or undue influence.
My real estate deal in Mississauga fell through. Can the firm help me?
John P. Mullen Law Office handles real estate litigation for both buyers and sellers whose transactions have broken down, working to protect the client's position when a deal falls apart.
Does the firm represent contractors as well as property owners in construction disputes?
John P. Mullen Law Office represents suppliers, equipment rental companies, subcontractors, general contractors, owners, and lenders in construction litigation, so it acts for more than one side of the industry depending on the case.
How long has John P. Mullen Law Office been practicing in the Mississauga area?
John P. Mullen Law Office is run by lawyer John Mullen, who was called to the Ontario Bar in 1978 and has appeared at all levels of court in Ontario since then.

Where to find them

106-218 Export Blvd. Mississauga, ON L5S 0A7 · 905-501-8778

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Listing compiled from the firm’s public website in September 2026. Verify licence status in the Law Society of Ontario directory ↗