diff --git a/backend/requirements.txt b/backend/requirements.txt
index 967ad4a07..c597947e4 100644
--- a/backend/requirements.txt
+++ b/backend/requirements.txt
@@ -45,6 +45,7 @@ pypdf==4.3.1
 docx2txt==0.8
 python-pptx==1.0.0
 unstructured==0.15.7
+nltk==3.9.1
 Markdown==3.7
 pypandoc==1.13
 pandas==2.2.2
diff --git a/pyproject.toml b/pyproject.toml
index 9d8ab8fee..98f9ccda0 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -52,6 +52,7 @@ dependencies = [
     "docx2txt==0.8",
     "python-pptx==1.0.0",
     "unstructured==0.15.7",
+    "nltk==3.9.1",
     "Markdown==3.7",
     "pypandoc==1.13",
     "pandas==2.2.2",