Montana ends a marriage through a district court case called a dissolution of marriage, which is what most people call a divorce. One or both spouses file a petition, the court confirms that Montana has authority and that the marriage is irretrievably broken, and a decree settles parenting, child support, maintenance, and property. This page is the starting point for the basics section of our Montana Divorce Guide.
Montana Calls It Dissolution of Marriage
The law is in Title 40, chapter 4 of the Montana Code Annotated. The legislature wrote the chapter's purposes into the statute: to promote the amicable settlement of disputes, to mitigate the potential harm to spouses and children caused by the process, and to make irretrievable breakdown "the sole basis" for ending a marriage (MCA § 40-4-101).
The vocabulary follows from that. The first paper is a petition, the reply is a response, and the case is titled "In re the Marriage of" the two spouses rather than one against the other (MCA § 40-4-103). A decree is not awarded to one spouse (MCA § 40-4-103(5)). Our glossary of Montana divorce terms covers the rest.
What the Court Must Find
Under MCA § 40-4-104(1), the district court enters a decree of dissolution if three things are true:
- Residency. One spouse was domiciled in Montana, or stationed here as a member of the armed services, and kept that domicile or military presence for the 90 days before filing. See the residency requirement.
- Irretrievable breakdown. The finding must be supported by evidence that the spouses lived separate and apart for more than 180 days before the case began, or that there is serious marital discord that adversely affects the attitude of one or both toward the marriage. A separation is one way to show this, not a precondition. See whether you have to be separated first.
- The four issues are addressed. To the extent it has jurisdiction, the court has considered, approved, or provided for parenting, child support, maintenance, and property.
Nothing in that list asks who caused the breakdown. Montana abolished the old fault defenses (MCA § 40-4-105(4)), which is why the only ground is that the marriage is broken, and why one spouse cannot block a divorce by refusing to agree.
The Four Things a Decree Settles
| Issue | How Montana decides it | MCA |
|---|---|---|
| Parenting | A parenting plan decided by the best interest of the child. The statutes say parenting plan, not custody. | §§ 40-4-212, 40-4-234 |
| Child support | An amount set under the state's uniform child support guidelines, which apply even when parents agree on a figure. | § 40-4-204 |
| Maintenance | Support for a spouse (alimony elsewhere), available only if the spouse lacks sufficient property and cannot be self-supporting through appropriate employment. | § 40-4-203 |
| Property and debt | An equitable apportionment of what either or both spouses own, however and whenever acquired. | § 40-4-202 |
Spouses can decide most of this themselves. A written separation agreement on property and maintenance is binding on the court unless the court finds it unconscionable. Terms about the support and parenting of children are not binding in the same way, and the court reviews them (MCA § 40-4-201(2)). Each topic has its own section of this guide, starting with property, maintenance, parenting plans, and child support.
The Routes From Petition to Decree
Either or both spouses may start the case (MCA § 40-4-105(2)). From there, how a case ends depends on how much the spouses agree on.
| Route | What it looks like |
|---|---|
| Summary dissolution | A short joint procedure for couples who meet every condition in the statute, including limits on assets, debts, and real property. |
| Joint petition | Both spouses file together as co-petitioners and present their written agreement. |
| One spouse files, then you agree | One spouse petitions and serves the other. The spouses settle the terms in a separation agreement the court reviews. |
| Contested case | The spouses cannot agree on one or more issues, so the court decides them after a hearing. |
| Default | The served spouse never responds, and the petitioner asks the court to enter a decree without them. |
How spouses reach agreement is a separate choice. Some negotiate directly, some use mediation, and some use a cooperative process. A&M Law is a Missoula family law firm that offers Cooperative Family Law, in which the firm serves as a neutral for both spouses, who meet together. In that process the firm represents the process rather than either spouse, and each spouse remains free to consult their own lawyer. The firm also represents individual clients in traditional divorce cases.
Agreement is not always safe or possible. If you are in danger, call 911. The National Domestic Violence Hotline is 1-800-799-7233, and our Montana Domestic Violence Guide explains orders of protection.
What Happens Once a Case Is Filed
Several things follow from filing, whichever route you take:
- An automatic economic restraining order. The clerk issues it with the summons. It restrains both spouses from transferring, encumbering, concealing, or disposing of marital property, with exceptions for necessities, the usual course of an existing business, and reasonable professional fees (MCA § 40-4-126).
- Financial disclosure. Each spouse serves a preliminary declaration of disclosure within 60 days of service of the petition, unless the spouses agree in writing to change or waive that exchange (MCA § 40-4-252).
- A minimum wait. When one spouse files and serves the other, the other has 21 days to respond, and a decree may not be entered until 21 days after service (MCA § 40-4-105(3)). See how long you have to wait.
- Temporary orders, if needed. Either spouse may ask for temporary maintenance, temporary child support, or an interim parenting plan while the case is pending (MCA §§ 40-4-121, 40-4-213).
Legal Separation, Invalidity, and Common-Law Marriage
Dissolution is not the only proceeding in the code. If a spouse asks for a legal separation instead and the other does not object, the court grants the decree in that form (MCA § 40-4-104(2)). A declaration of invalidity, which people call an annulment, is available only on the narrow grounds in MCA § 40-1-402. And because Montana recognizes common-law marriage, a couple who never had a ceremony may still need a dissolution to end their marriage.
When the Decree Is Final
A decree of dissolution is final when it is entered, subject to the right of appeal (MCA § 40-4-108(1)). On request, the court restores a spouse's maiden, birth, or former name (MCA § 40-4-108(5)). The provisions about children and support can be revisited later under their own statutes, while a property division may be changed only with both spouses' written consent or on grounds that justify reopening a judgment (MCA § 40-4-208(3)). If you are ready for the practical steps, see how to file for divorce in Montana or our Missoula divorce page.
This page explains Montana law in general as of the 2025 Montana Code Annotated. It is not legal advice about your specific situation.