diff --git a/packages/axe-core-api/axe-core-api.gemspec b/packages/axe-core-api/axe-core-api.gemspec
index 1a543e30..fa2d7f93 100644
--- a/packages/axe-core-api/axe-core-api.gemspec
+++ b/packages/axe-core-api/axe-core-api.gemspec
@@ -24,6 +24,9 @@ Gem::Specification.new do |spec|
   ]
 
   spec.add_dependency "dumb_delegator"
+  # used by virtus; including it to make sure we install the gem and do not
+  # rely on the standard library version, which will be removed in 3.5.0
+  spec.add_dependency "ostruct"
   spec.add_dependency "virtus"
 
   spec.add_development_dependency "bundler", "~> 2.1"
diff --git a/packages/axe-core-cucumber/axe-core-cucumber.gemspec b/packages/axe-core-cucumber/axe-core-cucumber.gemspec
index 2c623078..5342f094 100644
--- a/packages/axe-core-cucumber/axe-core-cucumber.gemspec
+++ b/packages/axe-core-cucumber/axe-core-cucumber.gemspec
@@ -23,6 +23,9 @@ Gem::Specification.new do |spec|
   ]
 
   spec.add_dependency "dumb_delegator"
+  # used by virtus; including it to make sure we install the gem and do not
+  # rely on the standard library version, which will be removed in 3.5.0
+  spec.add_dependency "ostruct"
   spec.add_dependency "virtus"
   # pin to a specific version of axe-core-api
   spec.add_dependency "axe-core-api", AxeCoreGems::VERSION
diff --git a/packages/axe-core-rspec/axe-core-rspec.gemspec b/packages/axe-core-rspec/axe-core-rspec.gemspec
index a7e9ecd6..8b82d08e 100644
--- a/packages/axe-core-rspec/axe-core-rspec.gemspec
+++ b/packages/axe-core-rspec/axe-core-rspec.gemspec
@@ -23,6 +23,9 @@ Gem::Specification.new do |spec|
   ]
 
   spec.add_dependency "dumb_delegator"
+  # used by virtus; including it to make sure we install the gem and do not
+  # rely on the standard library version, which will be removed in 3.5.0
+  spec.add_dependency "ostruct"
   spec.add_dependency "virtus"
   # pin to a specific version of axe-core-api
   spec.add_dependency "axe-core-api", AxeCoreGems::VERSION