diff --git a/requirements/dev.txt b/requirements/dev.txt
index 1d441ff..3253c2f 100644
--- a/requirements/dev.txt
+++ b/requirements/dev.txt
@@ -146,8 +146,6 @@ requests==2.32.5
 rich==14.2.0
     # via typer
 roman-numerals==4.1.0
-    # via roman-numerals-py
-roman-numerals-py==4.1.0
     # via sphinx
 rstcheck==6.2.5
     # via -r requirements/docs.in
@@ -157,7 +155,7 @@ shellingham==1.5.4
     # via typer
 snowballstemmer==3.0.1
     # via sphinx
-sphinx==8.2.3
+sphinx==9.1.0
     # via
     #   -r requirements/docs.in
     #   pallets-sphinx-themes
diff --git a/requirements/docs.in b/requirements/docs.in
index e2f0757..db3c3f7 100644
--- a/requirements/docs.in
+++ b/requirements/docs.in
@@ -1,6 +1,6 @@
 -r pkg.in
 Pallets-Sphinx-Themes~=2.0
-Sphinx~=8.0
+Sphinx~=9.1
 sphinx-issues~=5.0
 sphinxcontrib-log-cabinet~=1.0
 sphinx-tabs~=3.0
diff --git a/requirements/docs.txt b/requirements/docs.txt
index 96ad18a..8e827b8 100644
--- a/requirements/docs.txt
+++ b/requirements/docs.txt
@@ -70,8 +70,6 @@ requests==2.32.5
 rich==14.2.0
     # via typer
 roman-numerals==4.1.0
-    # via roman-numerals-py
-roman-numerals-py==4.1.0
     # via sphinx
 rstcheck==6.2.5
     # via -r requirements/docs.in
@@ -81,7 +79,7 @@ shellingham==1.5.4
     # via typer
 snowballstemmer==3.0.1
     # via sphinx
-sphinx==8.2.3
+sphinx==9.1.0
     # via
     #   -r requirements/docs.in
     #   pallets-sphinx-themes