Citation style
Full citation (MLA 9)
Accessed 23 June 2026.
In-text citation
("Source")
Why citation format matters for IB students
Every IB Extended Essay, Internal Assessment, and research-based assignment requires a consistent citation style. Examiners flag inconsistent or missing citations as academic honesty concerns, and the IA and EE criteria explicitly reward proper acknowledgement of sources. Choosing a style and applying it correctly throughout your work demonstrates scholarly rigour — and avoids the risk of unintentional plagiarism.
The three most commonly required styles for IB work are MLA 9th edition (common in English A, History, and humanities), APA 7th edition (used in Psychology, Economics, and sciences), and Chicago 17th edition (preferred for History extended essays and some humanities IAs). Check your teacher's or school's requirements before starting, as some coordinators specify a style for all internal assessments.
Citation style guide
MLA 9th Edition
Modern Language Association format is standard in literary studies, language courses, and humanities. In-text citations use the author's last name and page number in parentheses: (Smith 42). The Works Cited page lists sources alphabetically by author surname. MLA 9 introduced the concept of containers (e.g. a journal is a container for an article), which changes how online sources are formatted.
APA 7th Edition
American Psychological Association format is used in psychology, social sciences, and increasingly in economics and business. In-text citations include author and year: (Smith, 2021). The References page is formatted with hanging indents and includes DOIs for academic articles. APA 7 expanded guidance on online sources, removed the location of publishers, and updated rules for up to 20 authors.
Chicago 17th Edition
Chicago style appears in two forms: notes-bibliography (common in history, arts, and humanities) and author-date (used in sciences). Notes-bibliography uses footnotes or endnotes for in-text citation and a bibliography at the end. IB History extended essays most often require notes-bibliography format, where the first footnote citation is full and subsequent references can use a shortened form.
Frequently asked questions
Can I use the auto-fill for any URL?
Auto-fill works for most publicly accessible web pages and fetches the page title, author, and publication date from the page's metadata. Some paywalled or JavaScript-heavy sites may not return complete data — in those cases, fill in the fields manually.
Which citation style should I use for my EE?
Check your EE supervisor's guidance first. For History EEs, Chicago notes-bibliography is conventional. For English A EEs, MLA is standard. For science and economics EEs, APA is common, though MLA is also accepted. The IB does not mandate a specific style as long as you are consistent throughout the essay.
What counts as a proper citation for the IB?
Any widely recognised academic citation style (MLA, APA, Chicago, Harvard) is accepted by IB examiners. What matters is consistency: use one style throughout your work, cite every source you reference (including images, data, and paraphrased ideas), and provide a complete bibliography or works cited page.
Do I need to cite sources in my IA?
Yes — all sources referenced in your IA should be cited, including data, quotations, and the theoretical frameworks you apply. Failure to cite sources is treated as academic misconduct by the IB, regardless of whether it was intentional.