Introduction
Citing sources correctly is a cornerstone of academic integrity, and the Chicago Manual of Style (CMOS) offers two distinct systems—Notes‑and‑Bibliography (N&B) and Author‑Date—to accommodate the needs of humanities and social‑science scholars. Practically speaking, mastering these rules not only prevents plagiarism but also gives your paper a polished, professional appearance that reviewers and readers will respect. On top of that, when a work has multiple authors, the citation format changes subtly but predictably in each system. This guide walks you through every step of citing multiple‑author sources in Chicago style, from the first in‑text note to the final bibliography entry, and includes practical examples, common pitfalls, and a short FAQ for quick reference.
When to Use Which Chicago System
| Discipline | Preferred Chicago system | Typical citation location |
|---|---|---|
| History, literature, arts | Notes‑and‑Bibliography | Footnote or endnote, full bibliography |
| Sociology, anthropology, natural sciences | Author‑Date | Parenthetical in‑text citation, reference list |
| Interdisciplinary projects | Either, but be consistent | Follow your instructor or publisher’s guidelines |
Understanding which system you are required to use is the first step; the mechanics for handling multiple authors differ between the two.
General Rules for Multiple Authors
- Two authors – List both names in the order they appear on the title page.
- Three to ten authors – Include every author’s name in the first citation; later citations may be shortened.
- Eleven or more authors – List the first author followed by et al. in both notes and bibliography.
- Corporate or group authors – Treat the organization as the author; if a corporate author is accompanied by individual contributors, list the individuals first, then the organization.
These rules apply to books, journal articles, book chapters, conference proceedings, and online resources. The exact punctuation and formatting differ between N&B and Author‑Date, as detailed below.
Notes‑and‑Bibliography (N&B) System
First Footnote or Endnote
Two Authors
1. Firstname Lastname and Firstname Lastname, *Title of the Book* (Place of Publication: Publisher, Year), page number.
Example:
1. Sarah J. Smith and Michael R. Jones, *Urban Landscapes in the Digital Age* (New York: Routledge, 2022), 45.
Three to Ten Authors
1. Firstname Lastname, Firstname Lastname, and Firstname Lastname, *Title of the Book* (Place: Publisher, Year), page.
Example:
1. Emily A. Brown, Carlos D. Rivera, and Hannah L. Patel, *Climate Change and Coastal Communities* (Boston: Harvard University Press, 2021), 112‑13.
Eleven or More Authors
1. Firstname Lastname et al., *Title of the Book* (Place: Publisher, Year), page.
Example:
1. James K. Lee et al., *Advances in Genomic Editing* (San Francisco: BioScience Press, 2020), 78.
Subsequent Notes
- Two authors: Use “Lastname and Lastname, Title, page.”
- Three to ten authors: Use “Lastname et al., Title, page.” (the first author’s surname followed by et al.)
- Eleven or more authors: Continue with “Lastname et al., Title, page.”
Example (second citation):
2. Smith and Jones, *Urban Landscapes*, 102.
Bibliography Entry
The bibliography alphabetizes entries by the first author’s surname and follows a slightly different punctuation pattern.
Two Authors
Lastname, Firstname, and Firstname Lastname. *Title of the Book*. Place of Publication: Publisher, Year.
Example:
Smith, Sarah J., and Michael R. Jones. *Urban Landscapes in the Digital Age*. New York: Routledge, 2022.
Three to Ten Authors
Lastname, Firstname, Firstname Lastname, and Firstname Lastname. *Title of the Book*. Place: Publisher, Year.
Example:
Brown, Emily A., Carlos D. Rivera, and Hannah L. Patel. *Climate Change and Coastal Communities*. Boston: Harvard University Press, 2021.
Eleven or More Authors
Lastname, Firstname, et al. *Title of the Book*. Place: Publisher, Year.
Example:
Lee, James K., et al. *Advances in Genomic Editing*. San Francisco: BioScience Press, 2020.
Citing Book Chapters with Multiple Authors
When a chapter has a different author list from the edited volume, treat the chapter as an independent work That's the part that actually makes a difference..
First note:
1. Firstname Lastname, “Chapter Title,” in *Title of the Edited Book*, ed. Firstname Editor (Place: Publisher, Year), page.
Bibliography:
Lastname, Firstname. “Chapter Title.” In *Title of the Edited Book*, edited by Firstname Editor, page range. Place: Publisher, Year.
If the chapter itself has multiple authors, list them just as you would for a monograph, using “and” before the final name (two authors) or commas plus “and” (three to ten authors) Most people skip this — try not to. Less friction, more output..
Author‑Date System
The Author‑Date system integrates the citation directly into the text, using parentheses that contain the author(s)’ surnames and the year of publication. The reference list at the end follows a similar format to the bibliography but with slight variations No workaround needed..
In‑Text Citations
Two Authors
(Lastname and Lastname Year, page)
Example:
(Smith and Jones 2022, 45)
Three to Ten Authors
(Lastname et al. Year, page)
Example:
(Brown et al. 2021, 112‑13)
Eleven or More Authors
Same as three to ten authors: use et al. after the first surname Most people skip this — try not to. But it adds up..
(Lee et al. 2020, 78)
If you mention the authors in the narrative, only the year (and page, if needed) appears in parentheses:
Smith and Jones (2022) argue that...
Reference List Entry
The reference list is alphabetized by the first author’s surname and uses a hanging indent. Punctuation is crucial Simple, but easy to overlook..
Two Authors
Lastname, Firstname, and Firstname Lastname. Year. *Title of the Book*. Place of Publication: Publisher.
Example:
Smith, Sarah J., and Michael R. Jones. 2022. *Urban Landscapes in the Digital Age*. New York: Routledge.
Three to Ten Authors
Lastname, Firstname, Firstname Lastname, and Firstname Lastname. Year. *Title of the Book*. Place: Publisher.
Example:
Brown, Emily A., Carlos D. Rivera, and Hannah L. Patel. 2021. *Climate Change and Coastal Communities*. Boston: Harvard University Press.
Eleven or More Authors
Lastname, Firstname, et al. Year. *Title of the Book*. Place: Publisher.
Example:
Lee, James K., et al. 2020. *Advances in Genomic Editing*. San Francisco: BioScience Press.
Citing Journal Articles with Multiple Authors
The format mirrors that for books, with the addition of journal details.
In‑text (Author‑Date):
(Lastname et al. Year, page)
Reference list:
Lastname, Firstname, Firstname Lastname, and Firstname Lastname. Year. “Article Title.” *Journal Name* volume number (issue number): page range. DOI or URL (if applicable).
Example:
Garcia, Luis M., Priya K. Singh, and Ahmed R. Hassan. 2019. “Renewable Energy Policies in South Asia.” *Energy Policy* 128 (3): 456‑68. https://doi.org/10.1016/j.enpol.2019.01.012.
Common Pitfalls and How to Avoid Them
| Pitfall | Why it Happens | Correct Approach |
|---|---|---|
| Forgetting et al. after the first author for works with >10 authors | Manual counting error | Count authors; if >10, use “Lastname et al.” in both note and bibliography/reference list |
| Using “&” instead of “and” in N&B notes | Confusion with APA style | Chicago requires the word and (no ampersand) |
| Mixing up punctuation between N&B (periods) and Author‑Date (commas) | Switching between systems mid‑paper | Choose one system and apply its punctuation consistently |
| Omitting the editor’s name for a chapter in an edited volume | Assuming the chapter’s authors are enough | Include “in Title of Book, edited by Editor Name,” in the note and bibliography |
| Incorrect ordering of surnames and given names in the reference list | Misreading the manual’s “surname, given name” rule | Always start with the surname, followed by a comma and the given name(s) |
Frequently Asked Questions
Q1: How should I cite a source with exactly ten authors?
A: List all ten authors in the first footnote or in‑text citation. In subsequent notes, use “Firstauthor et al.” In the bibliography or reference list, include all ten names.
Q2: Do I need to include middle initials?
A: Yes, if they appear on the title page. Chicago prefers the full name as presented, including middle initials, to avoid ambiguity.
Q3: What if the source lists “and others” instead of naming all authors?
A: Treat it as a work with more than ten authors. Cite only the first author followed by et al. and do not write “and others” in the citation Took long enough..
Q4: Can I abbreviate “et al.” in the bibliography?
A: No. In the bibliography (or reference list), et al. is used only when the author count exceeds ten. For works with three to ten authors, list all names Simple, but easy to overlook..
Q5: How do I handle a source where the author list changes between print and online versions?
A: Cite the version you consulted. If the online version adds authors, reflect those in your citation; note the format (e.g., “Online version”) Not complicated — just consistent..
Conclusion
Citing multiple authors in Chicago style may initially seem daunting, but the pattern is logical: **two authors—list both; three to ten—list all the first time, then use et al.Whether you are employing the Notes‑and‑Bibliography system for a history paper or the Author‑Date system for a sociology article, the key is consistency, accurate punctuation, and adherence to the manual’s guidelines. ; eleven or more—use et al. from the start. By following the step‑by‑step examples in this guide, you can produce clean, error‑free citations that enhance the credibility of your work and keep you safely on the right side of academic integrity That alone is useful..
People argue about this. Here's where I land on it.
Quick reference cheat sheet
- Two authors: “Lastname and Lastname” (N&B) / (Lastname and Lastname Year) (Author‑Date)
- 3‑10 authors: First citation list all; later use “Lastname et al.”
- 11+ authors: “Lastname et al.” everywhere
- Bibliography/Reference list: Surname first, full names, et al. only for >10 authors
- Footnotes: Periods separate elements; commas separate author from title; page numbers after a comma
Keep this sheet handy while drafting, and your Chicago citations will be flawless every time.
