diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index dae1aec..d40caef 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,6 +15,10 @@ jobs:
           - { ruby: '3.0', mongodb: '4.4', gemfile: 'mongoid-8.0' }
           - { ruby: '3.1', mongodb: '4.4', gemfile: 'mongoid-8.0' }
           - { ruby: '3.2', mongodb: '4.4', gemfile: 'mongoid-8.0' }
+          - { ruby: '2.7', mongodb: '4.4', gemfile: 'mongoid-9.0' }
+          - { ruby: '3.0', mongodb: '4.4', gemfile: 'mongoid-9.0' }
+          - { ruby: '3.1', mongodb: '4.4', gemfile: 'mongoid-9.0' }
+          - { ruby: '3.2', mongodb: '4.4', gemfile: 'mongoid-9.0' }
     name: test (ruby=${{ matrix.entry.ruby }}, mongodb=${{ matrix.entry.mongodb }}), gemfile=${{ matrix.entry.gemfile }})
     env:
       BUNDLE_GEMFILE: gemfiles/${{ matrix.entry.gemfile }}.gemfile
diff --git a/CHANGELOG.md b/CHANGELOG.md
index cddf448..83ad2f1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 ### Unreleased - TBD
 
-* Your contribution here.
+* [#82](https://github.com/mongoid/mongoid-grid_fs/pull/82): Mongoid 9 support - [@Nilpointer](https://github.com/Nilpointer).
 
 ### 2.5.0 (2023/01/19)
 
diff --git a/gemfiles/mongoid-9.0.gemfile b/gemfiles/mongoid-9.0.gemfile
new file mode 100644
index 0000000..2ae32f4
--- /dev/null
+++ b/gemfiles/mongoid-9.0.gemfile
@@ -0,0 +1,6 @@
+source 'https://rubygems.org'
+
+gem 'mongoid', '~> 9.0.0'
+gem 'rails', '~> 7.0'
+
+gemspec path: '../'
diff --git a/mongoid-grid_fs.gemspec b/mongoid-grid_fs.gemspec
index 223aef7..d813606 100644
--- a/mongoid-grid_fs.gemspec
+++ b/mongoid-grid_fs.gemspec
@@ -24,5 +24,5 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'rubocop', '~> 1.36.0'
 
   spec.add_dependency 'mime-types', '>= 1.0', '< 4.0'
-  spec.add_dependency 'mongoid',    '>= 3.0', '< 9.0'
+  spec.add_dependency 'mongoid',    '>= 3.0', '< 10.0'
 end