Motion to Dismiss vs. Summary Judgment: What's the Difference?

A motion to dismiss under Fed. R. Civ. P. 12(b)(6) argues that even if everything in the complaint is true, the plaintiff loses. The court assumes the truth of well-pleaded factual allegations, draws reasonable inferences for the plaintiff, and asks whether those allegations state a plausible claim for relief. Ashcroft v. Iqbal, 556 U.S. 662, 678-79 (2009), sets the two-step method: strip out legal conclusions and threadbare recitals of the elements, then ask whether the remaining factual matter makes the claim plausible, not merely possible. Bell Atlantic Corp. v. Twombly, 550 U.S. 544 (2007), which retired the 'no set of facts' language of Conley v. Gibson, 355 U.S. 41 (1957), is the source of that standard.

A motion for summary judgment under Rule 56 argues that after the parties have gathered evidence, no reasonable jury could find for the nonmovant. The standard is 'no genuine dispute as to any material fact and the movant is entitled to judgment as a matter of law.' Fed. R. Civ. P. 56(a). Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 248 (1986), defines both key words: a fact is material only if the governing substantive law makes it matter, and a dispute is genuine only if the evidence would let a reasonable jury return a verdict for the nonmovant.

The clean way to hold this in your head: dismissal asks 'so what?' Summary judgment asks 'says who?'

On a 12(b)(6) motion the record is the pleading itself, plus exhibits attached to it, documents whose contents the complaint relies on and incorporates by reference, and matters subject to judicial notice. See Tellabs, Inc. v. Makor Issues & Rights, Ltd., 551 U.S. 308, 322 (2007). No affidavits. No deposition testimony. If the court considers material outside those categories, Rule 12(d) requires the motion to be converted to one for summary judgment, and all parties must get a reasonable opportunity to present pertinent material. Watch for that conversion trigger on exams; it is a favorite issue.

On summary judgment the record is everything Rule 56(c)(1)(A) lists: depositions, documents, electronically stored information, affidavits or declarations, stipulations, admissions, and interrogatory answers. The evidence need not be in admissible form at the summary judgment stage, but it must be capable of being presented in admissible form at trial; Rule 56(c)(2) lets a party object on that ground. Each asserted fact must be supported by a citation to particular parts of the record, not a general gesture at the file.

One exception to the 'no outside evidence' rule: a Rule 12(b)(1) motion attacking subject matter jurisdiction on factual grounds does allow the court to weigh evidence without converting the motion. That is a jurisdictional peculiarity, not a general 12(b) rule.

On a motion to dismiss the plaintiff bears the burden of having pleaded enough. The defendant does not have to disprove anything; it simply points to the gaps. Rule 9(b) raises the bar for fraud and mistake, requiring particularity as to the circumstances, and that heightened standard is where many complaints die.

On summary judgment the movant bears the initial burden of production, and Celotex Corp. v. Catrett, 477 U.S. 317, 322-25 (1986), explains how it varies. A defendant moving against a claim on which the plaintiff bears the trial burden of persuasion may satisfy its initial burden by pointing out the absence of evidence supporting an essential element; it need not submit affirmative evidence negating the element. A movant that bears the trial burden (a plaintiff moving on its own claim, or a defendant moving on an affirmative defense) must affirmatively establish every element.

Once the movant carries that initial burden, the nonmovant must do more than rest on the pleadings or offer a 'scintilla' of evidence. Anderson, 477 U.S. at 252. Matsushita Electric Industrial Co. v. Zenith Radio Corp., 475 U.S. 574, 586-87 (1986), adds that the nonmovant must present evidence permitting a rational inference in its favor, especially where the claim is economically implausible. But the court does not weigh evidence or assess credibility; it views the record in the light most favorable to the nonmovant. Tolan v. Cotton, 572 U.S. 650, 656-57 (2014) (per curiam), reversed a court for failing to do exactly that. The narrow counterweight is Scott v. Harris, 550 U.S. 372, 380-81 (2007), where video evidence 'blatantly contradicted' the nonmovant's account.

A Rule 12(b)(6) motion must be made before the responsive pleading. Fed. R. Civ. P. 12(b). Miss that window and the defense is not waived — Rule 12(h)(2) preserves failure to state a claim, and you can raise it by a Rule 12(c) motion for judgment on the pleadings, at trial, or by motion at trial. Consolidate your Rule 12 defenses in one motion; Rule 12(g)(2) bars a successive motion raising a defense that was available and omitted, and the waiver rules in Rule 12(h)(1) are strict for lack of personal jurisdiction, venue, process, and service.

Summary judgment ordinarily comes after discovery. Rule 56(b) sets a default deadline of 30 days after the close of all discovery, but that default is routinely displaced by local rule or scheduling order, so check both. A nonmovant facing an early motion should invoke Rule 56(d) with an affidavit specifying the facts it cannot yet present and the discovery it needs; a bare request for more time will not do. Rule 56(a) also permits partial summary judgment on a claim, a defense, or 'part of each claim or defense,' which is how parties narrow trials.

A 12(b)(6) dismissal is often without prejudice and accompanied by leave to amend, because Rule 15(a)(2) directs courts to give leave freely when justice so requires. Repeated failed amendments, futility, or a defect that cannot be cured (an expired limitations period appearing on the face of the complaint) can produce dismissal with prejudice, which is an adjudication on the merits for claim preclusion purposes. A summary judgment grant is always a merits judgment; there is no repleading your way out of it.

Denials differ too. A denial of either motion is generally not immediately appealable, because it is not a final judgment under 28 U.S.C. § 1291. The major exception is qualified immunity: Mitchell v. Forsyth, 472 U.S. 511 (1985), permits interlocutory appeal of a denial that turns on a question of law, while Johnson v. Jones, 515 U.S. 304 (1995), bars appeal of a denial resting on evidence sufficiency. Grants of either motion are reviewed de novo on appeal.

One more trap: Rule 56(f) lets a court grant summary judgment to a nonmovant, grant it on grounds not raised, or consider a fact undisputed on its own initiative — but only after giving notice and a reasonable time to respond.

Not uniformly, and this is where you have to check your jurisdiction. Many states copy the Federal Rules almost verbatim; others do not. On pleading, a substantial number of state high courts have expressly declined to adopt Twombly and Iqbal and retained the older notice-pleading standard, so the same complaint can survive in state court and fail in federal court. Some states also require fact pleading by statute regardless of Twombly.

The terminology and mechanics vary too. California, for example, uses a general demurrer rather than a 12(b)(6) motion and governs summary judgment by Code of Civil Procedure § 437c, which requires a separate statement of undisputed material facts and imposes a different initial burden on defendants than Celotex does; Aguilar v. Atlantic Richfield Co., 25 Cal. 4th 826 (2001), is the leading interpretation. Many federal districts have their own local separate-statement requirements as well. Before drafting, read the state rule, the local rule, and the judge's standing order together.

Identify the procedural posture first and let it dictate your tools. If the fact pattern gives you only a complaint, you are in Iqbal territory: separate conclusions from facts, test plausibility element by element against the substantive law, and flag any Rule 12(d) conversion problem if the movant attaches an affidavit. If the fact pattern gives you depositions and declarations, you are in Celotex and Anderson territory: identify the elements, identify who bears the trial burden on each, and ask whether the record permits a reasonable jury to find for the nonmovant.

Anchor materiality in the substantive law every time. Anderson makes clear that whether a fact is material depends entirely on the elements of the claim or defense, so a summary judgment answer that never states the elements has skipped the analysis. Then keep the roles straight: the judge decides whether a reasonable jury could find for the nonmovant, not what the jury should find. The summary judgment standard mirrors the Rule 50 judgment as a matter of law standard, which is why courts describe summary judgment as a pretrial directed verdict.