LaTeX Bibliography Not Showing? Fix BibTeX Issues in 5 Minutes

You've written your paper, added \cite{smith2024} everywhere, and hit compile — only to see [?] everywhere and no bibliography at all. This is one of the most frustrating LaTeX issues, and it appears on r/LaTeX almost daily. Let's fix it.

Why Citations Show as [?]

LaTeX uses a multi-pass compilation system. Citations require:

1. pdflatex main.tex — first pass (writes citation keys to .aux)
2. bibtex main — processes .bib file and creates .bbl
3. pdflatex main.tex — second pass (reads .bbl)
4. pdflatex main.tex — final pass (resolves cross-references)

If you only compile once, LaTeX literally doesn't have the bibliography data yet. Most editors handle this automatically, but sometimes it breaks.

Step-by-Step Fix

1. Check your .bib file path

The #1 cause: wrong filename in \bibliography{}:

% ❌ Wrong — don't include the .bib extension
\bibliography{references.bib}

% ✅ Correct
\bibliography{references}

2. Verify citation keys match exactly

BibTeX keys are case-sensitive. If your .bib file has Smith2024 but you wrote \cite{smith2024}, it won't match.

3. Choose the right backend

There are two bibliography systems — don't mix them:

% Option A: Classic BibTeX
\bibliographystyle{plain}
\bibliography{references}

% Option B: BibLaTeX (modern, more powerful)
\usepackage[backend=biber]{biblatex}
\addbibresource{references.bib}  % Note: .bib IS needed here
% ... at end of document:
\printbibliography

See our BibTeX vs BibLaTeX comparison to choose.

4. Clear auxiliary files and recompile

Corrupted .aux and .bbl files cause phantom errors. Delete all auxiliary files:

rm *.aux *.bbl *.blg *.log *.out
pdflatex main.tex
bibtex main
pdflatex main.tex
pdflatex main.tex

5. Check for BibTeX entry syntax errors

A single missing comma or brace in your .bib file silently breaks everything:

% ❌ Missing comma after year
@article{smith2024,
    author = {John Smith},
    title = {Great Paper},
    year = {2024}     % ← missing comma
    journal = {Nature}
}

% ✅ Correct
@article{smith2024,
    author = {John Smith},
    title = {Great Paper},
    year = {2024},
    journal = {Nature},
}

Using Zotero or Mendeley?

Export issues are common. Make sure you export as BibTeX (.bib), not RIS or EndNote. Check our Zotero + LaTeX guide for the correct export workflow.

The Easy Way: Let AI Handle It

Bibby AI has a built-in smart citation search — type a paper title or DOI and it inserts correctly formatted citations automatically. No .bib file management needed. Learn about AI features →