(a) Intervention of Right. Upon timely application anyone shall be permitted to intervene in an action: (1) When a statute confers an unconditional right to intervene; or (2) when the applicant claims an interest relating to the property or transaction which is the subject of the action and he is so situated that the disposition of the action may as a practical matter impair or impede his ability to protect that interest, unless the applicant's interest is adequately represented by existing parties.
Rule 24.Intervention
Current through June 1, 2026 · Last verified July 10, 2026
In one sentenceRule 24 lets a non-party join an existing lawsuit, either as of right when a statute grants that right or the case threatens an interest the applicant cannot otherwise protect, or with the court's permission when the applicant's claim shares a common question with the pending action.
Full Text of Rule 24
(b) Permissive Intervention. Upon timely application anyone may be permitted to intervene in an action: (1) When a statute confers a conditional right to intervene; or (2) when an applicant's claim or defense and the main action have a question of law or fact in common. When a party to an action relies for ground of claim or defense upon any statute or executive order administered by a federal or state governmental officer or agency or upon any regulation, order, requirement, or agreement issued or made pursuant to the statute or executive order, the officer or agency upon timely application may be permitted to intervene in the action. In exercising its discretion the court shall consider whether the intervention will unduly delay or prejudice the adjudication of the rights of the original parties.
Amendment History
The source reproduced here (current through June 1, 2026) records no amendment to this rule since its original adoption — no Credits line appears for it in the compiled rules. For the underlying adopting order and any later amendments, see the Colorado General Assembly.
Plain-English Summary
Rule 24 gives an outsider two paths into a pending lawsuit. Intervention of right applies when a statute grants an unconditional right to join, or when the applicant has a stake in the property or transaction at issue and the case's outcome could impair that stake without an existing party adequately representing it. When either condition is met, the court must let the applicant in.
Permissive intervention is discretionary. It covers cases where a statute gives a conditional right to intervene, where the applicant's claim or defense shares a common question of law or fact with the pending action, or where a government officer or agency has a stake in a statute, regulation, or order at issue in the case. Before granting permissive intervention, the court weighs whether letting the newcomer in will delay the case or prejudice the existing parties.
Either way, the person seeking to join must serve a motion to intervene on the existing parties, state the grounds for intervention, and attach a pleading laying out the claim or defense being asserted.
Frequently Asked Questions
What is the difference between intervention of right and permissive intervention in Colorado?
Intervention of right requires the court to let the applicant join because a statute or an unprotected property interest demands it, while permissive intervention leaves the decision to the court's discretion, usually because the applicant's claim shares a common question with the case.
How do I file a motion to intervene in a Colorado lawsuit?
Serve a motion on the existing parties under Rule 5, state the grounds for intervention, and attach a pleading setting out the claim or defense you want to raise.
Can a government agency intervene in a private lawsuit in Colorado?
Yes — when a party relies on a statute, executive order, or related regulation administered by a government officer or agency, that officer or agency may seek permissive intervention.
Can a court deny intervention even when the applicant has a right to intervene?
Only if an existing party already adequately represents the applicant's interest — otherwise, once the conditions for intervention of right are met, the court must permit it.
Source & verification. The rule text is reproduced verbatim from the
official Colorado Rules of Civil Procedure (Colo. R. Civ. P. 24). Prescribed by the Supreme Court of Colorado (C.R.S. § 13-2-108; Colo. Const. art. VI). The plain-English summary is original and written by us. Last verified July 10, 2026. ·
Official source
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