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Parties – Litigation #5

In civil litigation, identifying the proper parties is one of the most fundamental legal considerations. The question of who can sue and be sued is not always straightforward, it is governed by legal rules that define who has the legal capacity to participate in litigation. Understanding these rules is essential for ensuring a case is properly constituted.

This article provides a concise overview of the key principles regarding parties in civil litigation. We will discuss the parties to be added in a third-party claim in the next blog, “Pleadings.” In that blog, we are also going to cover topics such as counterclaims and cross-claims.

Adults and Legal Entities

  • Adults are presumed to have the capacity to sue and be sued. However, if there is doubt about a party’s capacity, the burden is on the person challenging it to prove the lack of capacity.
  • Legal persons, such as partnerships, sole proprietorships, and corporations (both business and nonprofit), also have the right to sue and be sued (governed by Rule 8 of the Rules of Civil Procedure).
  • Executors, administrators, trustees, and legal representatives of estates also have the right to commence or defend proceedings without requiring court permission (governed by Rules 9, 10, 74, etc.).
  • A personal representative can bring or defend an action on behalf of a deceased person’s estate, but when there is no personal representative, a litigation administrator may be appointed for that purpose.

Individuals Lacking Legal Capacity
Minors, mentally incompetent persons, and absentees (persons who have disappeared) are classified as “parties under disability” under Rule 7, these  individuals or entities do not have the capacity to participate in litigation on their own and require a representative.

  • Such individuals must be represented by a litigation guardian, who must apply to the court and consent to act in that capacity.
  • The litigation guardian must not have an interest adverse to the party under disability and must diligently act in their best interest.
  • Settlements involving a party under disability require court approval to be enforceable (Rule 7.08(1)).

A person not originally named in a lawsuit may apply to intervene as an added party by demonstrating:

  • A legal interest in the subject matter of the dispute;
  • The potential to be adversely affected by the outcome; or
  • A shared legal or factual issue with an existing party.

However, courts are generally reluctant to allow interventions unless it is clear that the individual was improperly omitted and has a material interest in the proceedings. Litigation is largely at the discretion of the plaintiff, who decides whom to sue.

Unlike added parties, “friends of the court” (amicus curiae) do not directly participate in the case but assist the court by providing legal expertise or perspectives.

  • Intervention as a friend of the court may occur either by leave of the court or at the invitation of a judge or master.
  • Such intervention is common in constitutional cases where broad legal principles are at stake.
  • For example, in Hansman v. Neufeld SCC 14 [2023], the Supreme Court of Canada allowed several intervenors to contribute arguments on free speech and LGBTQ+ rights.
  • Courts will consider whether the intervenor’s contribution would assist the court without unfairly prejudicing the parties.

Both joinder and consolidation result in a single, combined lawsuit but arise under different circumstances:

  • Joinder occurs when multiple parties are brought into a single lawsuit from the beginning.
  • Consolidation happens when separate lawsuits, involving overlapping issues, are merged into one proceeding to streamline litigation.
  • Mandatory Joinder
    • Certain parties must be joined in a lawsuit because their legal rights are directly affected by the outcome.
    • Example: If a beneficiary of an estate seeks a will interpretation, all executors must be named as defendants; failing to include one executor is not permitted, as all must be bound by the court’s decision.
  • Permissive Joinder
    • The plaintiff has discretion over which defendants to sue if they are not legally required to participate.
    • Example: A person injured in a condo balcony collapse may sue the builder but choose not to sue the materials supplier or city inspector if the claims are weaker or too complex.
    • The defendant, however, may seek to bring in additional parties through a third-party claim.
  1. Rule 5 of the Rules of Civil Procedure
    • Ensures that the right claims and parties are included in a lawsuit to avoid unnecessary litigation (CJA, s. 138).
    • Courts aim for efficiency and cost-effectiveness in managing cases.
  2. Joinder of Parties
    • Necessary parties (mandatory joinder, Rule 5.03):
      • Must be included due to their legal interest in the case.
    • Proper parties (permissive joinder, Rule 5.02):
      • May be included at the plaintiff’s discretion but are not required.
  3. Joinder of Claims
    • Plaintiffs may combine multiple claims in one lawsuit, provided they are manageable.
    • For example, an employment dispute may involve breach of contract, emotional distress, and human rights violations.
  4. Relief Against Joinder
    • If a case is too complex or costly, a judge may order some claims or parties removed under Rule 5.05.
  5. Consolidation of Actions (Rule 6)
    • Courts may consolidate cases or order them to be heard together to avoid duplication and inconsistent rulings, example: If three separate lawsuits involve the same core issue, they may be merged for efficiency.
    • Parties may move for consolidation at any stage, though it is usually done early in litigation.
  6. Separate Hearings (Bifurcation, Rule 6.1)
    • Even in consolidated cases, courts may order separate hearings for different issues (e.g., liability vs. damages).
  7. Severance of Claims
    • In some cases, courts may sever claims, allowing different claims within a lawsuit to proceed separately.
  8. Limitations Act, 2002 (s. 21(1))
    • Plaintiffs cannot circumvent limitation periods by belatedly adding parties through joinder or consolidation.

As seen above, even the seemingly simple question of “who can sue and be sued” is governed by complex legal rules. Choosing the correct parties and structuring a lawsuit properly is crucial for success in litigation. Additionally, issues such as litigation guardians, procedural safeguards for vulnerable parties, and intervention rules further complicate the matter. If you are involved in a legal dispute and unsure about the correct parties, it is advisable to consult a civil litigation lawyer as early as possible.


This blog provides general information, not legal advice. Always consult a qualified lawyer for your specific situation.