How to Modify Child Custody in Montana
Reviewed by DocDraft Legal Team · Montana · Last updated November 13, 2026
A Montana parent planning a move that will significantly affect the child's contact with the other parent has to do more than write a letter, because the warning itself is a motion filed in court. Modifying child custody in Montana means asking the district court that entered your parenting plan to amend it because the child's circumstances have changed since then. Montana's amendment statute speaks of a parenting plan rather than custody, so the request is an amendment of the parenting plan under MCA 40-4-219. No statute makes you wait any set time after the last plan. The gate is made of paper instead: under 40-4-220(1) you file an affidavit of supporting facts, the other parent may answer with opposing affidavits, and the judge must deny the motion unless those affidavits show adequate cause for a hearing. To win, you need facts that arose after the prior plan or were unknown to the court, a change in the child's circumstances, and proof that the amendment is necessary for the child's best interest. For a move, 40-4-217 requires the motion and a proposed revised residential schedule to be served personally or by certified mail at least 30 days before the move. The other parent then has 21 days to respond, and a parent who stays silent is treated as accepting the new schedule. A contested amendment costs $120 under 25-1-201(1)(a), and no fee is collected from you if the other parent signs a statement agreeing not to contest. Keep following your current plan until the court signs an order amending it. Attorney review of your filing is available through DocDraft.
Find out where you stand in Montana
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How do I change a parenting plan in Montana?
File a Motion to Amend Parenting Plan, a supporting affidavit and a proposed amended parenting plan with the Clerk of District Court in the county where the original plan was filed. Under MCA 40-4-220(1) the judge sets a show cause hearing only if the affidavits establish adequate cause. The statutory filing fee is $120.
Is there a waiting period to modify custody in Montana?
No. MCA 40-4-219 sets no minimum time after the last parenting plan. Two limits apply instead: a parenting plan action brought within 6 months after a child support action against that parent is presumed vexatious, and fees and costs must be assessed against a frivolous or repeated amendment found vexatious and harassing.
How much notice must a Montana parent give before moving with a child?
Any change of residence requires written notice to the other parent under MCA 40-4-217(1), with no day count. If the move will significantly affect the child's contact with the other parent, you must file a motion to amend the residential schedule and serve it at least 30 days before the proposed move.
At what age do a child's wishes count in a Montana custody change?
MCA 40-4-219(1)(a)(iii) tells the court to consider whether a child who is 14 or older desires the amendment. It is one factor, not a veto. A younger child's wishes still count as a best interest factor under 40-4-212(1)(b), and the judge may interview the child in chambers.
Montana parenting plan amendments at a glance
Changing child custody in Montana means asking the district court that entered your parenting plan to amend it because the child's circumstances have changed since the plan was made. Montana's amendment statutes speak of parenting plans, not custody, and the Judicial Branch says its courts use the term parenting time. Three features shape the process. There is no waiting period, but every contested motion must survive an adequate cause review of the affidavits before a hearing is set. A move that will significantly affect the child's contact with the other parent calls for a court motion served at least 30 days ahead, not just a letter. And the parent who receives that motion has 21 days to answer, because silence counts as accepting the proposed residential schedule.
A Montana parenting motion filed in the shadow of a support case
A child support action filed against a Butte father in April changes how a parenting motion he files that summer will be read. Under MCA 40-4-212(4)(a), a parenting plan action brought by a parent within 6 months after a child support action against that parent is presumed vexatious, although the presumption can be rebutted and gives way where applying it would be contrary to the child's best interest. His real reason is that his daughter's school moved her to a schedule that collides with his midweek overnight. If he can wait until October, that presumption no longer reaches him. If he cannot, his affidavit under 40-4-220(1) has to show adequate cause on the school facts alone, and 40-4-219(5) requires fees and costs against him if the court finds the motion vexatious and harassing.
Relevant Laws
MCA 40-4-219 (amendment of parenting plan)
Allows the court to amend a prior parenting plan on facts arising since it or unknown at its entry, where the child's circumstances have changed and the amendment is necessary for the child's best interest. Lists the age 14 consideration, the relocation factors, the proposed plan filing rule and mandatory fees for vexatious repeat amendments.
MCA 40-4-217 (notice of intent to move)
Requires written notice of any change of residence and, where the move will significantly affect the child's contact with the other parent, a motion to amend the residential schedule served at least 30 days before the move. Gives the other parent 21 days to respond and treats silence as acceptance.
MCA 40-4-220 (affidavit practice)
Requires a party seeking amendment of a final parenting plan to file a supporting affidavit, lets the other party file opposing affidavits, and directs the court to deny the motion unless adequate cause for hearing is shown. Subsection (2) covers ex parte interim plans in an emergency.
MCA 25-1-201 (fees of clerk of district court)
Sets a $120 fee for filing a petition for a contested amendment of a final parenting plan, and in subsection (4) bars the clerk from collecting it from the moving party when the other parent's signed statement agreeing not to contest is filed with the petition.
Montana Judicial Branch: Child Custody, Parenting Plans, Visitation forms
The state court forms page publishing the packets for amending a parenting plan when parents agree or disagree, the response to an amendment, the Notice of Intent to Move, an emergency interim plan motion, and a separate contempt packet for enforcing a plan.
Regional Variances
Montana parenting plan amendment levers at a glance
Waiting period before you may file
None. MCA 40-4-219 contains no minimum time after the last plan. Separately, 40-4-212(4)(a) presumes a parenting plan action vexatious if a parent brings it within 6 months after a child support action against that parent. That presumption is rebuttable and does not stop anyone filing.
Standard for an amendment
Facts that arose since the prior plan or were unknown to the court, a change in the child's circumstances, and an amendment necessary to serve the child's best interest. The court weighs the 40-4-212 factors plus parental agreement, integration into the petitioner's family, a child 14 or older who wants the change, and willful interference.
Procedural screen
Adequate cause on the affidavits. MCA 40-4-220(1) requires a supporting affidavit with the moving papers, permits opposing affidavits, and directs the court to deny the motion unless adequate cause for hearing is shown. An agreed amendment skips this step.
Relocation notice
Two tiers. Any change of residence needs written notice to the other parent, with no day count. A move that will significantly affect the child's contact needs a filed motion to amend the residential schedule, served personally or by certified mail at least 30 days before the move.
Relocation trigger
Effect on contact, not distance. MCA 40-4-217(2) switches on when the change in residence will significantly affect the child's contact with the other parent. No mileage figure and no state line test appear in the statute, so the measure is the existing contact pattern.
Relocation mechanism
Motion first, then a 21 day window. The other parent may respond with an alternate proposed residential schedule. Under 40-4-217(4) a properly served parent who files nothing within 21 days is treated as accepting the proposed schedule, and the court may reapportion transportation costs.
Court
The district court, captioned as the Montana judicial district court for the county. File with the Clerk of District Court in the county where the original plan was filed, or for a move, with the court that adopted the residential schedule or received the case on transfer.
Forms
No statute prescribes one. The Judicial Branch publishes packets for contested and agreed amendments and a response, and a Notice of Intent to Move numbered MP-904, filed with a proposed amended parenting plan, form MP-300, and a sheriff service request, form MP-401.
Filing fee
$120 for a petition for a contested amendment of a final parenting plan under MCA 25-1-201(1)(a). The clerk may not collect it from the moving parent if the other parent's signed statement agreeing not to contest is filed at the same time. Ask the clerk about any other charges.
Child's wishes
Age 14 is the statutory marker. MCA 40-4-219(1)(a)(iii) has the court consider whether a child 14 or older desires the amendment, without making it decisive. The child's wishes are also a general best interest factor, and 40-4-214 lets the judge interview the child in chambers on the record.
Suggested Compliance Checklist
Test the move against the contact standard
Before you sign a lease or accept a job days after startingAsk whether the new home will significantly affect the child's contact with the other parent. If it will, MCA 40-4-217(2) requires a filed motion served at least 30 days before the move. If it will not, you still owe written notice of the new residence under 40-4-217(1).
Check the calendar against any support case
Before you file days after startingNote the date of any child support action brought against you. MCA 40-4-212(4)(a) presumes a parenting plan action vexatious when a parent brings it within 6 months after that action. The presumption can be rebutted, but timing your filing outside the window removes it.
Assemble dated facts for the affidavit
Before drafting days after startingGather records showing what changed since the prior plan or what the court did not know: school schedules, messages, medical notes, missed exchanges. The adequate cause decision under MCA 40-4-220(1) is made on the affidavits, so the facts must be on paper and specific.
Complete the motion, affidavit and proposed plan
Once your facts are assembled days after startingUse the Montana Judicial Branch packet for amending a parenting plan when parents disagree, or the agreed packet if the other parent consents. Attach a proposed amended parenting plan as MCA 40-4-219(7) requires. For a move, add the Notice of Intent to Move, MP-904, with the statutory 21 day warning.
File with the Clerk of District Court
At least 30 days before any move that triggers the motion days after startingFile in the county where the original parenting plan was filed and pay $120 under MCA 25-1-201(1)(a), or file the other parent's signed statement agreeing not to contest so that fee is not collected from you. A statement of inability to pay is available if you cannot afford it.
Serve the other parent and file proof
Right after filing days after startingServe the motion, affidavit and proposed plan, and any signed Order to Show Cause, through the sheriff, a process server or, for a relocation motion, certified mail. Serve the other parent's attorney of record too. File the proof of service with the clerk.
Track the 21 day response window
21 days after service of a relocation motion days after startingUnder MCA 40-4-217(3) and (4) the other parent has 21 days to respond with an alternate proposed schedule, and silence counts as acceptance. If you are the parent served, file and serve your response inside that window. Attorney review of your filing is available.
Get the amending order signed
At the end of the case days after startingNothing changes until the judge signs an Order Amending Parenting Plan. Keep following the current plan until then, because departing from it on your own invites a contempt petition, and MCA 40-4-212(4)(b) presumes vexatious a motion to amend brought without a good faith effort to comply with the plan.
| Task | Description | Document | Days after starting |
|---|---|---|---|
| Test the move against the contact standard | Ask whether the new home will significantly affect the child's contact with the other parent. If it will, MCA 40-4-217(2) requires a filed motion served at least 30 days before the move. If it will not, you still owe written notice of the new residence under 40-4-217(1). | - | Before you sign a lease or accept a job |
| Check the calendar against any support case | Note the date of any child support action brought against you. MCA 40-4-212(4)(a) presumes a parenting plan action vexatious when a parent brings it within 6 months after that action. The presumption can be rebutted, but timing your filing outside the window removes it. | - | Before you file |
| Assemble dated facts for the affidavit | Gather records showing what changed since the prior plan or what the court did not know: school schedules, messages, medical notes, missed exchanges. The adequate cause decision under MCA 40-4-220(1) is made on the affidavits, so the facts must be on paper and specific. | - | Before drafting |
| Complete the motion, affidavit and proposed plan | Use the Montana Judicial Branch packet for amending a parenting plan when parents disagree, or the agreed packet if the other parent consents. Attach a proposed amended parenting plan as MCA 40-4-219(7) requires. For a move, add the Notice of Intent to Move, MP-904, with the statutory 21 day warning. | - | Once your facts are assembled |
| File with the Clerk of District Court | File in the county where the original parenting plan was filed and pay $120 under MCA 25-1-201(1)(a), or file the other parent's signed statement agreeing not to contest so that fee is not collected from you. A statement of inability to pay is available if you cannot afford it. | - | At least 30 days before any move that triggers the motion |
| Serve the other parent and file proof | Serve the motion, affidavit and proposed plan, and any signed Order to Show Cause, through the sheriff, a process server or, for a relocation motion, certified mail. Serve the other parent's attorney of record too. File the proof of service with the clerk. | - | Right after filing |
| Track the 21 day response window | Under MCA 40-4-217(3) and (4) the other parent has 21 days to respond with an alternate proposed schedule, and silence counts as acceptance. If you are the parent served, file and serve your response inside that window. Attorney review of your filing is available. | - | 21 days after service of a relocation motion |
| Get the amending order signed | Nothing changes until the judge signs an Order Amending Parenting Plan. Keep following the current plan until then, because departing from it on your own invites a contempt petition, and MCA 40-4-212(4)(b) presumes vexatious a motion to amend brought without a good faith effort to comply with the plan. | - | At the end of the case |
Frequently Asked Questions
Other Montana guides
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Adverse Possession in Montana: Five Years and Every Tax Bill
Asset Protection Planning in Montana (2026)
Dealing With Debt Collectors in Montana (2026)
Delinquent Property Taxes in Montana: The Lien Is Assigned Over the Counter, and an Occupied Home Is Auctioned Rather Than Deeded
Expunging a Criminal Record in Montana (2026)
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