Ontario Court of Appeal Quashes Mexico's NAFTA Arbitration Appeal

The Ontario Court of Appeal, in 2026, quashed Mexico's appeal of a Superior Court decision that had set aside an arbitration award, ruling that Section 11 of Ontario's International Commercial Arbitration Act, 2017 (ICAA) prohibits appeals from Superior Court decisions concerning an arbitral tribunal's jurisdiction.

This significant ruling clarifies the scope of appeal rights in international commercial arbitration in Ontario, particularly regarding jurisdictional challenges. It reinforces the finality of Superior Court decisions on arbitral jurisdiction under the ICAA, even when an award has been rendered, rather than just a preliminary ruling. The dispute originated from an arbitration commenced in Toronto in 2018 under Chapter 11 of NAFTA by claimants against Mexico. The tribunal issued an award in 2024, finding it lacked jurisdiction. The claimants then successfully applied to the Ontario Superior Court of Justice to set aside the award in April 2026, arguing jurisdictional error and apprehension of bias. Mexico appealed this decision, but the claimants moved to quash the appeal, asserting that s. 11 of the ICAA expressly prohibited such appeals. Mexico contended that s. 11 applied only to preliminary jurisdictional decisions, not awards, and that Article 34 of the UNCITRAL Model Law on International Commercial Arbitration allowed for an appeal in this context. The Court of Appeal rejected Mexico's interpretation, affirming the restrictive nature of s. 11.

The legal context for this decision is primarily Ontario's International Commercial Arbitration Act, 2017 (ICAA), which incorporates the UNCITRAL Model Law on International Commercial Arbitration. Specifically, the interpretation of s. 11 of the ICAA was central, as it governs the limited circumstances under which appeals from Superior Court decisions relating to arbitral jurisdiction are permitted. The case also touches upon the framework of international investment law, given its origin in a Chapter 11 NAFTA arbitration. The key parties involved were the Ontario Court of Appeal, the Ontario Superior Court of Justice, the United Mexican States, and the claimants in Grace v. United Mexican States. The outcome of the underlying arbitration on the merits, beyond the jurisdictional finding, is not reported in the excerpt.

For practitioners, this decision underscores the critical importance of understanding the stringent limitations on appealing jurisdictional decisions in international arbitrations seated in Ontario. Attorneys advising clients must recognize that s. 11 of the ICAA creates a high bar for challenging Superior Court decisions on jurisdiction, irrespective of whether the tribunal's jurisdictional finding was preliminary or embedded within a final award. This means that jurisdictional arguments must be meticulously prepared and presented at the arbitral tribunal and Superior Court stages, as subsequent appellate review is severely restricted. The ruling emphasizes Ontario's commitment to the finality and efficiency of international arbitration, aligning with the pro-arbitration stance often found in Model Law jurisdictions. It also highlights the need to carefully consider the interplay between domestic arbitration legislation and international treaty obligations.