diff --git a/docs-requirements.txt b/docs-requirements.txt
index bef1fe2d7..c535b8afd 100644
--- a/docs-requirements.txt
+++ b/docs-requirements.txt
@@ -15,5 +15,5 @@ jsonschema>=4.10.0,<4.18.0  # newer versions break sphinxcontrib-openapi
 sphinxcontrib-redoc~=1.6
 
 # required for building OpenAPI spec
-apispec[yaml,validation]~=4.0
+apispec[yaml,validation]~=6.0
 marshmallow~=3.10  # needed for apidocs
diff --git a/httpstan/openapi.py b/httpstan/openapi.py
index 69520cdc0..ca9a3126d 100644
--- a/httpstan/openapi.py
+++ b/httpstan/openapi.py
@@ -55,5 +55,4 @@ def openapi_spec() -> apispec.APISpec:
     spec.path(path="/v1/models/{model_id}/fits/{fit_id}", view=views.handle_get_fit)
     spec.path(path="/v1/models/{model_id}/fits/{fit_id}", view=views.handle_delete_fit)
     spec.path(path="/v1/operations/{operation_id}", view=views.handle_get_operation)
-    apispec.utils.validate_spec(spec)
     return spec