Whether you’re a multinational structuring a cross-border M&A, a private client planning an estate, or a business fighting a CRA reassessment, Canada’s tax bar includes a small group of lawyers whose technical mastery and courtroom grit set them apart. This SEO-friendly, in-depth guide profiles the top 10 tax lawyers in Canada (2025), explains what makes each one exceptional, and helps you pick the right advisor for your needs.
Why these names matter (quick context)
Legal market guides and peer-reviewed rankings such as Chambers Canada, ITR World Tax, Legal 500, and Best Lawyers identify leading practitioners based on client feedback, peer reference checks, and a track record of high-stakes work. The lawyers below are repeatedly recommended across those sources for transactional savvy, dispute resolution, and technical depth.
Firoz Ahmed — Osler, Hoskin & Harcourt LLP
Specialties: Corporate tax, M&A tax structuring, cross-border reorganizations, partnerships.
Why he’s top: Firoz is widely recognized for translating complex transaction structures into pragmatic tax solutions for high-value deals. He combines a strong academic/technical background with hands-on M&A experience for public and private clients. Clients call him the “go-to” for tough acquisition and equity financing tax issues.
Jerald M. Wortsman — Torys LLP
Specialties: Cross-border corporate tax, complex M&A, banking & finance tax, tax controversy.
Why he’s top: As head of Torys’ tax team, Jerald advises on large-scale, cross-jurisdictional transactions and is routinely retained on matters that blend corporate finance with tax innovation. His bandwidth handling of multi-jurisdiction clients gives him an edge in transactions tied to the U.S. market.
Jeffrey C. Trossman — Blake, Cassels & Graydon LLP (Blakes)
Specialties: Transactional tax, tax audits & disputes, tax advice for financial institutions.
Why he’s top: A seasoned senior statesperson in Canadian tax, Jeffrey’s experience spans decades of M&A and tax controversy. He is frequently described as technically authoritative and trusted by in-house counsel and CRA officials alike.
R. Ian Crosbie — Davies Ward Phillips & Vineberg LLP
Specialties: High-value corporate tax, private equity, tax structuring for complex finance transactions.
Why he’s top: Ian is a classical transaction tax expert—clients praise his technical brilliance and practical solutions for private equity and public company transactions. He’s often engaged for deal-critical tax opinions and structuring advice.
Raj Juneja — McCarthy Tétrault LLP
Specialties: Corporate & international tax planning, tax controversy, cross-border issues (especially Canada-US).
Why he’s top: Raj is known for creative but commercially sensible tax advice and for leading on some of Canada’s largest transactions and disputes with the CRA. He’s viewed as a commercial strategist who anchors technical tax solutions to business objectives.
Carrie Smit — Goodmans LLP
Specialties: Capital markets tax, corporate reorganizations, cross-border M&A, and private equity tax.
Why she’s top: Carrie heads Goodmans’ tax team and is praised for clear, practical counsel on capital markets and restructuring mandates—where timing and tax sensitivity matter. She’s often tapped for high-profile corporate transactions.
Barbara J. Worndl — Aird & Berlis LLP
Specialties: International & corporate tax, REITs and real estate, partnership and fund structuring.
Why she’s top: Barbara is a long-standing Senior Statesperson in the Canadian tax world who frequently chairs and authors for the Canadian Tax Foundation. She’s especially noted for cross-border tax expertise and real estate investment structures.
Ian J. Gamble — Thorsteinssons LLP
Specialties: Corporate & international tax, CRA audit defence, tax litigation, resource sector tax.
Why he’s top: Ian is a veteran tax counsel with deep experience in mining, energy, and resource transactions—areas where Canadian tax nuance is critical. His boutique experience often means hands-on involvement in client files from planning through dispute.
Mitchell J. Sherman — Goodmans LLP
Specialties: Transactional tax (cross-border deals), private equity, corporate reorganizations.
Why he’s top: Recognized as a senior statesperson in tax, Mitchell’s long track record of advising on major cross-border deals and his contributions to tax scholarship make him a go-to choice for complex transactional matters.
Martha MacDonald — Torys LLP
Specialties: Tax litigation, CRA disputes, appellate work, tax controversy strategy.
Why she’s top: Martha leads Torys’ tax controversy practice and is known for persuasive advocacy in trial and appellate courts as well as strategic problem-solving during CRA audits and appeals. Clients value her courtroom experience when disputes can’t be settled administratively.
How these lawyers were selected (methodology)
This list synthesizes:
- Chambers Canada rankings and individual profiles (authoritative peer and client research).
- Firm bios and recent press (to confirm specialties and high-impact matters).
- Cross-checks with ITR/Legal 500/Best Lawyers and Canadian market reporting to ensure breadth across transaction, controversy, and private wealth practices.
What makes a “top” tax lawyer in Canada (practical checklist)
When you evaluate an elite tax lawyer, look for:
- Technical mastery — deep knowledge of the Income Tax Act, case law, and administrative practice.
- Track record — high-value M&A, precedent-setting litigation, or repeated wins before the Tax Court.
- Cross-border capability — especially Canada-US expertise for multinationals.
- Reputation with tax authorities — credibility with the CRA and tax adjudicators can materially change outcomes.
- Clarity and commercial sense — advice that ties tax strategy to business goals, not just theory.
- Accessibility of senior counsel — make sure the named partner will actually work your file.
- Thought leadership — articles, presentations, or leadership in the Canadian Tax Foundation signals authority.
Which lawyer should you pick for different needs?
- High-value M&A / capital markets: Firoz Ahmed, R. Ian Crosbie, Jeffrey Trossman, Mitchell Sherman.
- Cross-border / international tax planning: Jerald Wortsman, Raj Juneja, Ian Gamble.
- Tax controversy & litigation: Martha MacDonald, Jeffrey Trossman, Barbara Worndl.
- Private wealth, trusts and estates: Paul Gibney (noted boutique specialist), Barbara Worndl.
How to engage (practical tips)
- Prepare a concise brief — timeline, amounts at stake, prior assessments, and supporting documents.
- Ask about fee structure up front — hourly, capped, or blended; controversial work often uses phased billing.
- Request bios and sample matters — top lawyers can and will confirm similar experience (suitably anonymized).
- Check conflicts — large firms often represent adversaries; ensure there’s no conflict before engagement.
- Seek a short strategy memo — a 1–2 page plan from the lawyer shows how they’ll approach the issue and helps in decision-making.
Frequently Asked Questions (SEO-friendly)
Q: Are these lawyers only for big corporations?
A: No. Many (e.g., Paul Gibney, Ian Gamble) advise private clients and owner-managers. Boutique specialists also represent individuals in CRA disputes.
Q: How do I check a tax lawyer’s track record?
A: Use Chambers/ITR/Best Lawyers and the firm’s pressroom to find cases and recognitions; ask the lawyer for anonymized matter summaries during initial engagement.
Q: Will a top tax lawyer handle my CRA audit?
A: Yes — many of these lawyers are routinely engaged to lead audits and to escalate disputes to the Tax Court when needed. Martha MacDonald and Jeffrey Trossman are examples of litigators with appellate experience.
Final thoughts
Canada’s elite tax lawyers combine rigorous legal analysis with business instincts. They win complex deals, preserve tax outcomes, and resolve high-stakes disputes. The ten practitioners profiled here are consistently recognized in independent rankings and by clients for delivering those results. If your matter involves material tax exposure, cross-border complexity, or a contested assessment, reaching out to one of these lawyers (or the small boutiques that partner with them) is a sensible next step.
