diff --git a/README.md b/README.md
index 5f34a4b..2e8e227 100644
--- a/README.md
+++ b/README.md
@@ -31,6 +31,7 @@ A curated list of awesome data labeling tools
 * [TagEditor](https://github.com/d5555/TagEditor) - Annotation tool for spaCy
 * [SMART](https://github.com/RTIInternational/SMART) - Smarter Manual Annotation for Resource-constrained collection of Training data
 * [docanno](https://github.com/doccano/doccano) - Open source text annotation tool for machine learning practitioner
+* [pdfanno](https://github.com/paperai/pdfanno) - Linguistic Annotation and Visualization Tool for PDF Documents
 
 #### Audio