Can a party file a motion for new trial after summary judgment?

Yes, a party may file a timely motion for new trial or motion to modify/reform after a no-evidence summary judgment, and the trial court retains plenary power for the period prescribed by Tex. R. Civ. P. 329b. But a motion for new trial/reconsideration generally cannot be used to raise new claims, new defenses, or evidence that should have been presented in response to the summary-judgment motion; for amended claims, the party ordinarily must have sought leave to amend before the summary-judgment hearing or obtained leave from the court before filing an untimely amendment. Tex. R. Civ. P. 329b [2][4]

Short answer

After a no-evidence summary judgment dismissing all claims, the losing party may:

1. File a motion for new trial or motion to modify, correct, or reform the judgment within the deadlines in Tex. R. Civ. P. 329b.[2][4]
2. Ask for leave to amend pleadings, but the success of that request depends on timing and prejudice; if the amendment is sought after the summary-judgment hearing or after judgment, the court may deny it, and appellate courts generally presume leave was denied absent an order showing otherwise.[3]

Governing rules

1. Motion for new trial / reconsideration after summary judgment

Under Tex. R. Civ. P. 329b, a motion for new trial must be filed within 30 days after the judgment is signed, and if timely filed, it extends plenary power.[2][4] Texas practice treats a motion for new trial filed after summary judgment as a motion for reconsideration, because there was no trial.[1]

Texas courts also hold that a party cannot use a post-judgment motion to raise arguments that were not presented in the summary-judgment response. The Texas Supreme Court has stated that issues first raised in a motion for new trial/reconsideration are waived.[1]

“Raising an argument or objection in a motion for new trial or reconsideration for the first time is not sufficient because all issues must be raised in the response.”[1]

That principle was applied in Kelley-Coppedge, Inc. v. Highlands Ins. Co., 980 S.W.2d 462 (Tex. 1998), and reaffirmed in Godoy v. Wells Fargo Bank, N.A., 575 S.W.3d 531 (Tex. 2019).[1]

2. Request to add additional claims

Texas Rule 63 allows amendments without leave until seven days before trial, unless a scheduling order provides otherwise, but summary-judgment practice imposes a separate timing rule. Under Tex. R. Civ. P. 166a(c), after the summary-judgment hearing has passed, an amended pleading ordinarily requires leave of court to be considered.[3]

The Houston First Court held in Austin v. Countrywide Home Loans, 261 S.W.3d 68 (Tex. App.—Houston [1st Dist.] 2008, pet. denied) that once the hearing date for a summary-judgment motion has passed, a party must secure a written order granting leave to file an amended pleading; absent an order, the appellate court assumes leave was denied.[3]

Practical effect

Important caveat

If the additional claims were not part of the case before the summary judgment and were not preserved in the response, a motion for new trial is generally not the proper vehicle to “bootstrap” them into the case.[1] Texas law is also clear that parties cannot create fact issues in a motion for new trial/reconsideration that should have been raised earlier.[1]

So, in your scenario: they may file a motion for new trial, but that motion usually cannot be used to add new claims or arguments that were omitted from the summary-judgment response. A separate request for leave to amend may be made, but after summary judgment it is discretionary and often too late unless the court grants leave before considering the amendment.[2][3][4]