diff --git a/.github/workflows/monkey.yml b/.github/workflows/monkey.yml
new file mode 100644
index 0000000000..ad08acc452
--- /dev/null
+++ b/.github/workflows/monkey.yml
@@ -0,0 +1,22 @@
+---
+name: Check Monkey Patches
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    env:
+      CI: true
+      TESTOPTS: "-v"
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up Ruby 3.0
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 3.0
+          bundler-cache: true
+      - name: bundle
+        run: bundle install --jobs 4 --retry 3
+      - name: Run RSpec Monkey Patch check
+        run: bundle exec rspec spec/check_monkey_patches.rb
diff --git a/spec/check_monkey_patches.rb b/spec/check_monkey_patches.rb
new file mode 100644
index 0000000000..99f3a41bb2
--- /dev/null
+++ b/spec/check_monkey_patches.rb
@@ -0,0 +1,226 @@
+# frozen_string_literal: true
+
+raise 'Monkey patches spec must be run before loading Mongoid' if defined?(Mongoid::Document)
+
+require 'rspec'
+
+# Require dependency gems that add monkey patches
+require 'active_support/all'
+require 'bson'
+require 'openssl'
+require 'ruby2_keywords'
+
+CLASSES = [
+  Object,
+  Array,
+  BigDecimal,
+  Date,
+  DateTime,
+  FalseClass,
+  Float,
+  Hash,
+  Integer,
+  Module,
+  NilClass,
+  Range,
+  Regexp,
+  Set,
+  String,
+  Symbol,
+  Time,
+  TrueClass,
+  ActiveSupport::TimeWithZone,
+  BSON::Binary,
+  BSON::Decimal128,
+  BSON::ObjectId,
+  BSON::Regexp,
+  BSON::Regexp::Raw
+].freeze
+
+instance_methods = CLASSES.index_with(&:instance_methods)
+class_methods = CLASSES.index_with(&:methods)
+
+require 'mongoid'
+
+ADDED_INSTANCE_METHODS = instance_methods.each_with_object({}) do |(klass, methods), hash|
+  hash[klass] = klass.instance_methods.sort - methods - (hash[Object] || [])
+end
+
+ADDED_CLASS_METHODS = class_methods.each_with_object({}) do |(klass, methods), hash|
+  hash[klass] = klass.methods.sort - methods - (hash[Object] || []) - ADDED_INSTANCE_METHODS[Object]
+end
+
+EXPECTED_INSTANCE_METHODS = {
+  Object => %i[
+    __add__
+    __add_from_array__
+    __array__
+    __deep_copy__
+    __evolve_object_id__
+    __expand_complex__
+    __find_args__
+    __intersect__
+    __intersect_from_array__
+    __intersect_from_object__
+    __mongoize_object_id__
+    __mongoize_time__
+    __setter__
+    __sortable__
+    __to_inc__
+    __union__
+    __union_from_object__
+    blank_criteria
+    blank_criteria?
+    do_or_do_not
+    ivar
+    mongoize
+    multi_arged?
+    numeric?
+    regexp?
+    remove_ivar
+    resizable?
+    substitutable
+    you_must
+  ].freeze,
+  Array => %i[
+    __evolve_date__
+    __evolve_time__
+    __sort_option__
+    __sort_pair__
+    delete_one
+  ].freeze,
+  Date => %i[
+    __evolve_date__
+    __evolve_time__
+  ].freeze,
+  DateTime => %i[
+    __evolve_date__
+    __evolve_time__
+  ].freeze,
+  Float => %i[
+    __evolve_date__
+    __evolve_time__
+  ].freeze,
+  Hash => %i[
+    __consolidate__
+    __sort_option__
+    _mongoid_unsatisfiable_criteria?
+    delete_id
+    extract_id
+    to_criteria
+  ].freeze,
+  Integer => %i[
+    __evolve_date__
+    __evolve_time__
+    unconvertable_to_bson?
+  ].freeze,
+  Module => %i[
+    re_define_method
+  ].freeze,
+  NilClass => %i[
+    __evolve_date__
+    __evolve_time__
+    __expanded__
+    __override__
+    collectionize
+  ].freeze,
+  Range => %i[
+    __evolve_date__
+    __evolve_range__
+    __evolve_time__
+  ].freeze,
+  String => %i[
+    __evolve_date__
+    __evolve_time__
+    __expr_part__
+    __mongo_expression__
+    __sort_option__
+    collectionize
+    mongoid_id?
+    unconvertable_to_bson
+    unconvertable_to_bson=
+    unconvertable_to_bson?
+  ].freeze,
+  Symbol => %i[
+    __expr_part__
+    add_to_set
+    all
+    asc
+    ascending
+    avg
+    desc
+    descending
+    elem_match
+    eq
+    exists
+    first
+    gt
+    gte
+    in
+    intersects_line
+    intersects_point
+    intersects_polygon
+    last
+    lt
+    lte
+    max
+    min
+    mod
+    mongoid_id?
+    ne
+    near
+    near_sphere
+    nin
+    not
+    push
+    sum
+    with_size
+    with_type
+    within_box
+    within_polygon
+  ].freeze,
+  Time => %i[
+    __evolve_date__
+    __evolve_time__
+  ].freeze,
+  ActiveSupport::TimeWithZone => %i[
+    __evolve_date__
+    __evolve_time__
+    _bson_to_i
+    bson_type
+    to_bson
+  ].freeze,
+  BSON::Decimal128 => %i[
+    __evolve_decimal128__
+  ].freeze
+}.freeze
+
+EXPECTED_CLASS_METHODS = {
+  Object => %i[
+    __mongoize_fk__
+    demongoize
+    evolve
+    re_define_method
+  ].freeze,
+  Float => %i[__numeric__].freeze,
+  Integer => %i[__numeric__].freeze,
+  String => %i[__expr_part__].freeze,
+  Symbol => %i[add_key].freeze,
+  Time => %i[configured].freeze
+}.freeze
+
+RSpec.describe('Monkey patches') do
+
+  CLASSES.each do |klass|
+
+    context klass.name do
+      it 'adds no unexpected instance methods' do
+        expect(ADDED_INSTANCE_METHODS[klass]).to eq(EXPECTED_INSTANCE_METHODS[klass]&.sort || [])
+      end
+
+      it 'adds no unexpected class methods' do
+        expect(ADDED_CLASS_METHODS[klass]).to eq(EXPECTED_CLASS_METHODS[klass]&.sort || [])
+      end
+    end
+  end
+end