One of the most misunderstood parts of Texas civil procedure is what happens after a judgment is signed. Many people assume the case is immediately final. In reality, Texas law gives trial courts a period of time—known as plenary power—during which the court can still change its judgment.

Understanding Texas Rule of Civil Procedure 329b is critical because it governs motions for new trial, motions to modify judgment, and the timeline for appeals.

If these deadlines are missed, a party can lose the right to challenge a judgment entirely.

What Is a Motion for New Trial in Texas?

A motion for new trial asks the trial court to set aside the judgment and conduct another trial. These motions are often filed when a party believes:

• The court made a legal error
• The jury verdict was unsupported by evidence
• Newly discovered evidence exists
• Procedural irregularities affected the fairness of the trial

Texas Rule of Civil Procedure 329b(a) sets the first key deadline:

“A motion for new trial, if filed, shall be filed prior to or within thirty days after the judgment or other order complained of is signed.”
— Tex. R. Civ. P. 329b(a)

This 30-day window is strict. If no qualifying post-judgment motion is filed within that time, the trial court’s ability to modify the judgment becomes very limited.

The Trial Court’s “Plenary Power”

Even after signing a judgment, a Texas trial court still retains authority over the case for a limited time. This authority is known as plenary power.

Texas Rule of Civil Procedure 329b(d) explains:

“The trial court, regardless of whether an appeal has been perfected, has plenary power to grant a new trial or to vacate, modify, correct, or reform the judgment within thirty days after the judgment is signed.”

In other words, for the first 30 days after judgment, the court can freely change its ruling.

However, if a motion for new trial or motion to modify the judgment is filed, the timeline changes dramatically.

How Post-Judgment Motions Extend the Court’s Power

When a timely post-judgment motion is filed, the court’s authority over the case is extended.

Rule 329b(c) provides:

“In the event an original or amended motion for new trial is not determined by written order signed within seventy-five days after the judgment was signed, it shall be considered overruled by operation of law on expiration of that period.”

This means:

• The court has 75 days to rule on the motion.
• If it does nothing, the motion is automatically denied.

After that happens, the court’s plenary power continues for another 30 days.

Rule 329b(e) states:

“If a motion for new trial is timely filed, the trial court… has plenary power to grant a new trial or to vacate, modify, correct, or reform the judgment until thirty days after all such timely-filed motions are overruled.”

This timeline is crucial because it can extend the trial court’s control over the case from 30 days to as long as 105 days.

Why Rule 329b Matters for Appeals

Texas appellate deadlines are tied directly to Rule 329b.

Normally, a party must file a notice of appeal within 30 days of the judgment. However, if certain post-judgment motions are filed—such as a motion for new trial or motion to modify judgment—the appellate deadline can extend to 90 days.

Because of this, Rule 329b often determines:

• Whether an appeal is timely
• Whether a trial court still has jurisdiction
• Whether a judgment can still be changed

Once plenary power expires, the trial court loses jurisdiction to modify the judgment, except through limited procedures such as a bill of review.

Common Strategic Uses of Rule 329b

Experienced litigators frequently use Rule 329b strategically. Some common reasons include:

Preserving Error

A motion for new trial can preserve certain issues for appeal.

Extending the Appeal Deadline

Filing a qualifying post-judgment motion can extend the notice-of-appeal deadline from 30 days to 90 days.

Giving the Trial Court a Chance to Fix Errors

Trial judges sometimes correct mistakes when the issue is raised in a post-judgment motion.

Negotiating Post-Judgment Settlements

The extended timeline can give parties time to negotiate before the case moves to the appellate court.

What Happens After Plenary Power Expires?

Once plenary power ends, the trial court generally cannot change its judgment.

Texas courts consistently hold that orders signed after plenary power expires are void, meaning they have no legal effect.

At that point, a losing party’s options are typically limited to:

• Appealing the judgment
• Filing a restricted appeal
• Filing a bill of review under limited circumstances

Final Thoughts

Texas Rule of Civil Procedure 329b is one of the most important procedural rules in Texas litigation. It determines:

• When a motion for new trial must be filed
• How long a trial court retains authority over its judgment
• Whether the deadline to appeal has been extended

Because the timelines are strict, parties involved in litigation should seek legal advice quickly after a judgment is entered.

Missing a Rule 329b deadline can permanently eliminate important legal rights.

At David C. Barsalou, Attorney at Law, PLLC, we help clients navigate business, family, tax, estate planning, and real estate matters ranging from document drafting to litigation with clarity and confidence. If you’d like guidance on your situation, schedule a consultation today. Call us at (713) 397-4678, email barsalou.law@gmail.com, or reach us through our Contact Page. We’re here to help you take the next step.