Does Kostyniuk & Greenside represent insurance companies, or individuals too?

The firm offers legal services to insurance companies, brokers, independent adjusters, corporations, and individuals across the insurance law field.

Can Kostyniuk & Greenside help with a claim at the Licence Appeal Tribunal?

Yes. The firm's lawyers appear regularly as counsel on statutory accident benefits disputes and on priority and loss transfer arbitrations at the Licence Appeal Tribunal.

How long has Kostyniuk & Greenside been practicing in Toronto?

The firm has served individual and corporate clients, including some of Canada's insurers, for approximately 40 years.

Where is the firm located?

The office is at 5468 Dundas Street West, Suite 300, in Toronto's Etobicoke area, near the Six Points intersection at Kipling Avenue.

Does Kostyniuk & Greenside offer articling positions?

Yes. The firm runs an articling program built around its civil litigation practice, pairing students with an associate mentor and giving them exposure to pleadings, motions, mediations, and trial work.

Kostyniuk & Greenside Lawyers | LawOnline Directory

About Kostyniuk & Greenside Lawyers

Kostyniuk & Greenside is a Toronto firm that focuses on insurance law, based on Dundas Street West in the city's Etobicoke area. It has provided legal services to insurers, brokers, independent adjusters, corporations and individuals in the insurance field for approximately 40 years. Its litigation practice covers personal injury, statutory accident benefits disputes before the Licence Appeal Tribunal, insurance coverage disputes, loss transfer and subrogation claims, long-term disability insurance claims, product liability, class actions and commercial disputes, along with corporate transactions and administrative law work.

The firm takes its name from two lawyers. Nestor E. Kostyniuk, a partner, was called to the Ontario Bar in 1979, became a Certified Specialist in Civil Litigation in 1992, and has concentrated in insurance law ever since. Derek R.J. Greenside was called to the Bar in 1987, became a Certified Specialist in Civil Litigation in 1999, and is now retired from active practice. Today the team runs to about twenty lawyers, and the firm points to its history as trial lawyers as part of why many of its current lawyers first joined as articling students before staying on as associates or partners.

Practice areas

Personal Injury

Business & Corporate Law

Insurance Law

Class Actions

Civil Litigation & Dispute Resolution

Administrative & Regulatory Law

Milestones & recognition

Nestor E. Kostyniuk served as President of the Toronto Lawyers Association in 2010 and is a past chair of the Bar Dispute Resolution Group Forum.
Derek R.J. Greenside became a Certified Specialist in Civil Litigation in 1999, one of the credentials the firm's litigation practice is built on.
In 2026, a lawyer at the firm received the Canadian Defence Lawyers' Richard B. Lindsay Exceptional Young Lawyer Award, given for contributions to the legal profession.

In the community

A partner at the firm serves on the Board of the Toronto Lawyers Association and represents it on the Roundtable of Legal Diversity Associations (RODA).
In 2015, a partner at the firm founded a pro bono initiative in the United Kingdom that continues to operate today through a law school there.
During law school, an associate at the firm volunteered with Pro Bono Students Canada, focusing on human rights advocacy for adults with disabilities.

Lawyers 21

Certified Specialists

A designation granted by the Law Society of Ontario, not a self-declared area of focus.

Nestor E. Kostyniuk["Civil Litigation"]

This firm’s lawyers at a glance

Called to the bar: 1979–2026 · median 12 years in practice 19 of 21 lawyers
Law schools: Osgoode Hall Law School (3), University of Windsor (2), Bond University, City University Law School, London, England, Kent University of Law, Ottawa University and 7 more 16 of 21 lawyers
Languages on the roster: English, French

Who handles what

The neighbourhood

Kostyniuk & Greenside's office sits on Dundas Street West in Toronto's Islington-City Centre West area, near the Six Points intersection where Dundas meets Kipling Avenue. Dundas Street began in 1793-1794 as a road built by the Queen's Rangers connecting Coote's Paradise, later renamed Dundas, to London, Ontario; an extension east toward York, now Toronto, followed later, in 1796, and a stretch of the road is still known as the Governor's Road. The Six Points interchange itself, a freeway-style junction built in 1961, was rebuilt between 2017 and 2020 into ordinary at-grade intersections as part of an effort to restore a walkable streetscape to the area.

Frequently asked questions

What areas of insurance law does Kostyniuk & Greenside handle?: The firm handles statutory accident benefits disputes before the Licence Appeal Tribunal, insurance coverage disputes, loss transfer and subrogation claims, long-term disability insurance claims, product liability, and class actions, along with personal injury and commercial disputes.
Does Kostyniuk & Greenside represent insurance companies, or individuals too?: The firm offers legal services to insurance companies, brokers, independent adjusters, corporations, and individuals across the insurance law field.
Can Kostyniuk & Greenside help with a claim at the Licence Appeal Tribunal?: Yes. The firm's lawyers appear regularly as counsel on statutory accident benefits disputes and on priority and loss transfer arbitrations at the Licence Appeal Tribunal.
How long has Kostyniuk & Greenside been practicing in Toronto?: The firm has served individual and corporate clients, including some of Canada's insurers, for approximately 40 years.
Where is the firm located?: The office is at 5468 Dundas Street West, Suite 300, in Toronto's Etobicoke area, near the Six Points intersection at Kipling Avenue.
Does Kostyniuk & Greenside offer articling positions?: Yes. The firm runs an articling program built around its civil litigation practice, pairing students with an associate mentor and giving them exposure to pleadings, motions, mediations, and trial work.

Where to find them

5468 Dundas Street W., Suite 300, Toronto, Ontario, M9B 6E3 · 416-762-8238

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