diff --git a/tests/constraints.in b/tests/constraints.in
index 9933e5f451..e776c29219 100644
--- a/tests/constraints.in
+++ b/tests/constraints.in
@@ -1,5 +1,5 @@
 # Known limitations for indirect/transitive dependencies.
 resolvelib < 1.1.0
-sphinx == 6.2.1
+sphinx == 5.3.0
 rstcheck < 6  # rstcheck 6.x has problem with rstcheck.core triggered by include files w/ sphinx directives https://github.com/rstcheck/rstcheck-core/issues/3
 antsibull-docs == 2.3.1  # currently approved version
diff --git a/tests/requirements-devel.txt b/tests/requirements-devel.txt
index 6f579b850b..735d7f17be 100644
--- a/tests/requirements-devel.txt
+++ b/tests/requirements-devel.txt
@@ -118,7 +118,7 @@ six==1.16.0
     # via twiggy
 snowballstemmer==2.2.0
     # via sphinx
-sphinx==6.2.1
+sphinx==5.3.0
     # via
     #   -c constraints.in
     #   -r requirements.in
diff --git a/tests/requirements.txt b/tests/requirements.txt
index abafd991a8..2645c62efb 100644
--- a/tests/requirements.txt
+++ b/tests/requirements.txt
@@ -113,7 +113,7 @@ six==1.16.0
     # via twiggy
 snowballstemmer==2.2.0
     # via sphinx
-sphinx==6.2.1
+sphinx==5.3.0
     # via
     #   -c constraints.in
     #   -r requirements.in