Article III. Civil Appeals Rules · Part D. Briefs · Last amended 2008 · Last verified July 20, 2026
In one sentenceRule 343 sets the deadlines for filing the appellant's, appellee's, and reply briefs, including special schedules for cross-appeals and separate appeals.
(a)Time. Except as provided in subparagraph (b) below and elsewhere in these rules (see
Rules 306, 307, 308, 315, and 317), the brief of the appellant shall be filed in the reviewing court within 35 days from the filing of the record on appeal. Within 35 days from the due date of the appellant’s brief, or in the case of multiple appellants, the latest due date of any appellant’s brief, the appellee shall file his or her brief in the reviewing court. Within 14 days from the due date of the appellee’s brief, or in the case of multiple appellees, the latest due date of any appellee’s brief, the appellant may file a reply brief.
(b)Cross-Appeals and Separate Appeals. Unless otherwise ordered by the reviewing court or a judge thereof, briefs of cross-appellants and separate appellants shall be filed as follows:
(1)Cross-Appeals. A cross-appellant shall file a single brief as appellee and cross-appellant at the time his or her brief as appellee is due; the appellant’s answer to the arguments on the cross-appeal shall be included in appellant’s reply brief, which shall be filed within 35 days from the due date of the single brief filed by the cross-appellant; and the cross-appellant may file a reply brief confined strictly to replying to those arguments raised on the cross-appeal within 14 days after the due date of the appellant’s reply brief.
(2)Separate Appeals. A separate appellant shall follow the same briefing schedule as prescribed for the appellant. All appellees shall file their briefs within 35 days of the due date of appellants’ briefs. Any replies may be filed within 14 days of the due date of appellees’ briefs.
(c)Extending or Shortening Time. The reviewing court or a judge thereof, sua sponte or upon the motion of a party supported by affidavit or verification by certification under section 1-109 of the Code of Civil Procedure showing a good cause, may extend or shorten the time of any party to file a brief. (See Rule 361.)
Plain-English Summary
Rule 343 runs the appellate briefing clock. The appellant's opening brief is due 35 days after the record on appeal is filed. The appellee then has 35 days from the appellant's due date to respond, and the appellant gets 14 more days after that for a reply brief.
Cases with cross-appeals or multiple appellants follow adjusted timing. A cross-appellant files one combined brief serving as both its appellee brief and its opening brief on the cross-appeal, and the original appellant then gets a longer window to answer both. Separate appellants generally follow the appellant's schedule, while all appellees get the same 35 days measured from the appellants' due dates.
None of these deadlines are set in stone. A reviewing court or judge can shorten or extend any of them on a motion supported by an affidavit or certification showing good cause, under the general motion procedure in Rule 361.
Frequently Asked Questions
How long does an appellant have to file the opening brief?
35 days from the filing of the record on appeal, unless another rule sets a different schedule.
How much time does the appellee get to respond?
35 days from the appellant's brief due date, or from the latest due date if there are multiple appellants.
How long does the appellant have to file a reply?
14 days from the appellee's brief due date, or from the latest due date if there are multiple appellees.
How does a cross-appeal change the briefing schedule?
The cross-appellant files one brief covering both its role as appellee and cross-appellant, and the original appellant then has 35 days to reply to both, followed by a shorter reply window for the cross-appellant limited to the cross-appeal issues.
Can these deadlines be extended?
Yes, the reviewing court or a judge can extend or shorten any filing deadline on a motion supported by an affidavit or certification showing good cause.
Committee Comments and Commentary
(March 26, 2008)
Paragraph (b)(1) was amended to make clear that the appellant has 35 days from the due date of the single brief filed by the cross-appellant to file a reply brief that includes the appellant’s answer to the arguments on the cross-appeal rather than the 14 days generally allowed for filing reply briefs set forth in paragraph (a). This amendment makes no substantive change to this rule.
(December 17, 1993)
Paragraph (a) has been modified to make clear that only one brief need be filed when responding to multiple briefs of opponents filed at separate times.
Paragraph (b)(2) has been changed to eliminate the former practice of automatic staggering of the briefing schedule in cases involving separate appeals.
(Revised September 1, 1974)
This rule, governing the times for filing and serving briefs in all reviewing courts, is based in part upon former Supreme Court Rules 41(2) and (4) and Second, Third, Fourth, and Fifth District (and earlier Uniform) Appellate Court Rule 9. The provision in the former rule that if a brief or abstract was not filed within the time prescribed the appeal would be dismissed on the call of the docket was omitted as both too strict and unnecessary. The court has the inherent power to dismiss an appeal for any breach of its rules, although a less drastic remedy would normally suffice. In the rare instances in which a brief of an appellant is inexcusably not filed on time, the court can exercise this power without any provision in the rule specifically authorizing it to do so.
The committee recommended 35 days as the time period for the main briefs best calculated to fit the requirements of the bar and the reviewing courts. The committee recognized the importance of providing a long enough period to permit the preparation of a brief in the ordinary case without the necessity of an extension of time and a short enough period to permit prompt disposition of the business of the reviewing courts. Five weeks would seem to be a realistic compromise. The time for filing the reply brief was fixed at 14 days, consistent with the multiples-of-seven policy.
The rule establishes the time for filing briefs in all cases on appeal from final judgments of the circuit court, whether to the Appellate Court (Rules 303 and 304), or directly to the Supreme Court (Rule 302). It applies to appeals from orders of the circuit court granting a new trial (Rule 306) and to interlocutory appeals by permission (Rule 308), subject to the provisions in those rules measuring the 35 days allowed for the filing of the appellant’s brief from the date of the order allowing the appeal, rather than from the filing of the record on appeal. Rule 307 provides for a special, shorter timetable for the filing of briefs in interlocutory appeals as of right. Appeals from the Appellate Court to the Supreme Court on certificate (Rule 316) are governed by Rule 343, but appeals from the Appellate Court to the Supreme Court on petition for leave to appeal (Rule 315) or petition for appeal as a matter of right (Rule 316) are governed by the provisions of Rule 315(g), which sets forth the timetable for filing briefs in such cases. Paragraph (c) of Rule 343 is applicable to all appeals.
In 1969 former paragraph (b) was relettered (c) and present paragraph (b) was inserted to provide the bar with explicit directions as to the briefs on cross-appeals and separate appeals.
The rule was amended in 1974 to delete material referring to appeals on petition for leave to appeal. This material was placed in Rules 306, 308, and 315. As part of the same amendment the words “with proof of service” were deleted and Rule 344(a) amended to set forth the requirement of filing proof of service.
Amendment History
Amended October 21, 1969, effective January 1, 1970; amended effective September 1, 1974; amended December 17, 1993, effective February 1, 1994; amended May 24, 2006, effective September 1, 2006; amended March 26, 2008, effective July 1, 2008.
Source & verification. Rule text, official Committee Comments, and
amendment history are reproduced verbatim from the Illinois Supreme Court Rules,
promulgated by the Supreme Court of Illinois. Last verified July 20, 2026.
· Official source
Also known as:brief filing deadlinesreply brief due datecross-appeal briefing scheduleextending brief deadline appealappellate briefing timeline