How to Write a Declaration for Child Custody in California

To write a declaration for child custody in California, you put your sworn testimony on Judicial Council Form MC-030, organize the facts around the child’s best interest factors, keep it inside the 10-page limit, sign it under penalty of perjury, and file and serve it with the request or response it supports. The judge reads this document before the hearing, so it often carries more weight than anything you say in court.

What a Custody Declaration Actually Does

A declaration is your written testimony to the judge. It doesn’t stand alone. It backs up a specific request in the case: either a Request for Order (Form FL-300) if you’re the parent asking the court to make a custody decision,¹ or a Responsive Declaration to Request for Order (Form FL-320) if you’re answering a request the other parent filed.² The FL-300 or FL-320 frames the legal ask. The declaration tells the story that supports it.

The Forms You’ll Use

The declaration itself goes on Form MC-030. The form has pre-printed fields for the case caption, case number, and the perjury language you’ll sign at the bottom.³ Writing space is limited. When you need more room, use Form MC-031, the Attached Declaration, as a continuation stapled to your MC-030. MC-031 is never filed on its own.⁴ Both forms are free from the California Courts website.

Formatting Rules and the Page Limit

California courts are strict about formatting, and a declaration that doesn’t comply can be rejected at the filing window. Lines must be one-and-a-half or double-spaced and numbered consecutively down the left margin, with each page starting over at line 1.⁵ Fill in the caption completely: both parties’ names, the court, and the case number.

Then there’s the cap. Declarations filed with a Request for Order or a Responsive Declaration are limited to 10 pages. Reply declarations are limited to 5. Expert witness declarations and situations where the judge grants permission are the only exceptions.⁶ Ten pages goes fast. Every paragraph needs to earn its space.

Organize Around the Best Interest Factors

California law directs judges to decide custody based on the child’s best interest, with health, safety, and welfare as the primary concern.⁷ The statute names specific factors the court must weigh, and shaping your declaration around them is what separates a useful document from a personal grievance.

The factors the court considers include:

The child’s health, safety, and welfare. This is the umbrella. Physical health, emotional wellbeing, education, daily stability.
Any history of abuse by a parent against the child, the other parent, or someone in the household. The court can require independent corroboration such as police reports, child protective services records, or medical documentation.
The nature and amount of contact with both parents, and each parent’s willingness to support the child’s relationship with the other parent.
Habitual use of controlled substances or alcohol by either parent. Corroboration from law enforcement, medical providers, or treatment facilities may be required.

The court cannot consider a parent’s sex, gender identity, gender expression, or sexual orientation.⁸ It also cannot hold a parent’s immigration status against them.⁹

The court also weighs which parent is more likely to allow frequent and continuing contact with the other parent.⁹ A declaration built entirely around attacking the other parent can backfire for that reason. Judges want to see that you support the child’s relationship with both parents, unless safety concerns make that inappropriate.

Write Specifics, Not Character Descriptions

The most common mistake in custody declarations is writing in generalities. Saying the other parent “doesn’t care about the children’s education” gives the judge nothing to work with. Saying “On March 12, 2025, I received a call from the school counselor informing me that the children had missed eight days of school during their father’s custodial time that month” gives the judge a fact to evaluate. Dates, names, locations, specifics.¹⁰

Everything must come from your personal knowledge. Describe what you saw, what you heard, what you did, what happened to you. Don’t speculate about the other parent’s motivations and don’t repeat what a friend told you. That’s hearsay and the judge will disregard it. If a teacher, doctor, or therapist has relevant information, they should write their own declaration, or you should attach their records as exhibits.

A structure that works for most people:

Your relationship with the child. Daily involvement, who handles school, medical appointments, meals, bedtime, activities.
The child’s current routine and stability. School, community ties, friendships, what would be disrupted by a change.
Concrete concerns about the other parent. Dated incidents, not character attacks. Late exchanges, missed medical appointments, unsafe situations, each described factually.
What you’re asking for and why. Tie your requested arrangement to the child’s routine, education, and emotional needs.

Keep the tone calm. Judges read dozens of these, and the ones full of anger and name-calling lose credibility fast. “The other parent showed up visibly intoxicated at the school pickup on October 3, 2025, and I have a text message from the teacher confirming this” carries far more weight than “he’s a drunk who doesn’t care about his kids.” Let the facts do the emotional work.

If Domestic Violence Is Part of the Case

Address it directly. California law creates a rebuttable presumption that awarding custody to a parent who has committed domestic violence within the past five years is detrimental to the child’s best interest. The presumption applies to both physical and legal custody, and the abusive parent can only overcome it by showing a preponderance of evidence that custody would be appropriate despite the history.

The definition is broad. It includes not just physical harm or attempted harm, but also threats, harassment, destroying personal property, and disturbing the peace of the other parent or household members. When you raise domestic violence in your declaration, include every relevant detail: dates, what happened, whether police were called, whether a restraining order was issued, and any documentation. Photographs of injuries, police reports, and medical records go in as exhibits. Because the court can require independent corroboration, more documentation is stronger.⁸

Attaching Exhibits

Exhibits are the documents that back up what you wrote. Screenshots of text messages, emails, photographs, school attendance records, police reports, medical records. Only attach documents you actually reference in the declaration.

Introduce each exhibit in the body of the declaration before it appears. A standard phrasing: “A true and correct copy of the text message exchange from June 5, 2025, is attached as Exhibit A.” Label exhibits sequentially, starting with A, and put the label on the first page of each so the judge can find it quickly.

Before attaching anything, redact sensitive personal information. Social Security numbers, bank account numbers, and dates of birth for minor children should be blacked out from anything you file. Many courts now make filings available electronically, and unredacted personal data creates identity theft risks. Keep an unredacted copy for your own records.

Signing Under Penalty of Perjury

A declaration is not valid until you sign it with the required perjury language. If you sign inside California, the statement reads: “I declare under penalty of perjury that the foregoing is true and correct,” followed by the date, the city where you signed, and your signature. If you sign outside California, the statement must add “under the laws of the State of California.”¹¹ MC-030 has this language pre-printed, so you generally just fill in the date, location, and signature.

Take the language seriously. Knowingly including false statements can result in a perjury charge, which is a felony in California.¹² Beyond the criminal exposure, a judge who catches a false statement will question everything else you wrote. Credibility is the currency of custody litigation.

Filing and Serving

File the signed original with the court clerk in person, by mail, or through an electronic filing service provider if your county offers one. The clerk keeps the original and returns a file-stamped copy. Filing fees vary by county.

Watch the deadlines. California Rules of Court set specific timeframes for when moving papers and responsive papers must be filed and served before a hearing.¹³ Miss the deadline and the judge may not read your declaration, or the hearing may be continued. Check Rule 5.92 and your local court’s requirements as soon as you have a hearing date, then work backward.

After filing, serve the other parent. You cannot hand the papers over yourself. California requires a third party who is not involved in the case to complete service, either in person or by mail. That person then fills out a Proof of Service: FL-330 for personal service or FL-335 for service by mail.¹⁴¹⁵ File the completed Proof of Service with the court. Without it, the judge may refuse to proceed because there’s no proof the other parent received notice.

If You’re Responding to the Other Parent

When the other parent files a Request for Order, you have the right to respond with your own declaration on the Responsive Declaration (FL-320).² The 10-page limit still applies.⁶ Everything above about specifics, personal knowledge, exhibits, and signing applies the same way.

Resist the urge to rebut every line the other parent wrote. Focus on factual inaccuracies that matter and on presenting your own evidence for the arrangement you want. If the other parent wrote that you missed a school conference and you actually attended, correct that with specifics and attach a sign-in sheet if you have one. Don’t burn page space disputing minor details that won’t move the judge. Your goal is to show what arrangement serves the child, not to win the argument with your co-parent.

1
California Courts. Request for Order (FL-300)
2
California Courts. Responsive Declaration to Request for Order (FL-320)
3
California Courts. Declaration (MC-030)
4
California Courts. Attached Declaration (MC-031)
5
Judicial Branch of California. Rule 2.108. Spacing and Numbering of Lines
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Judicial Branch of California. Rule 5.111. Declarations Supporting and Responding to a Request for Order
7
California Legislative Information. California Code FAM 3020
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California Legislative Information. California Code FAM 3011
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California Legislative Information. California Code FAM 3040
10
Santa Barbara County Superior Court. How to Write a Declaration
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California Legislative Information. California Code CCP 2015.5
12
California Legislative Information. California Code PEN 118
13
Judicial Branch of California. Rule 5.92. Request for Court Order; Responsive Declaration
14
California Courts. Proof of Personal Service (FL-330)
15
California Courts. Proof of Service by Mail (FL-335)