diff --git a/.github/workflows/judoscale-good_job-test.yml b/.github/workflows/judoscale-good_job-test.yml
index 02497470..d36ab30b 100644
--- a/.github/workflows/judoscale-good_job-test.yml
+++ b/.github/workflows/judoscale-good_job-test.yml
@@ -28,6 +28,11 @@ jobs:
             ruby: "2.6"
           - gemfile: Gemfile-activerecord-7-0
             ruby: "2.6"
+          # GoodJob v4+ dropped support for Ruby 2.6/2.7, we test it against these Gemfiles.
+          - gemfile: Gemfile
+            ruby: "2.7"
+          - gemfile: Gemfile-activerecord-7-0
+            ruby: "2.7"
           # AR 6.1 stable doesn't play nice with Ruby 3.2+. Fixes have been backported
           # https://github.com/rails/rails/pull/46895, but no release is planned.
           # To avoid testing against 6-1-stable branch, we'll just skip those for now.
diff --git a/judoscale-good_job/Gemfile-activerecord-6-1 b/judoscale-good_job/Gemfile-activerecord-6-1
index cb65ad6c..fec73dc2 100644
--- a/judoscale-good_job/Gemfile-activerecord-6-1
+++ b/judoscale-good_job/Gemfile-activerecord-6-1
@@ -4,6 +4,7 @@ gemspec name: "judoscale-good_job"
 
 gem "judoscale-ruby", path: "../judoscale-ruby"
 gem "activerecord", "~> 6.1"
+gem "good_job", "~> 3.30"
 gem "pg"
 gem "minitest"
 gem "rake"
diff --git a/judoscale-good_job/judoscale-good_job.gemspec b/judoscale-good_job/judoscale-good_job.gemspec
index b2cde907..97b104d6 100644
--- a/judoscale-good_job/judoscale-good_job.gemspec
+++ b/judoscale-good_job/judoscale-good_job.gemspec
@@ -26,5 +26,5 @@ Gem::Specification.new do |spec|
   spec.required_ruby_version = ">= 2.6.0"
 
   spec.add_dependency "judoscale-ruby", Judoscale::VERSION
-  spec.add_dependency "good_job", ">= 3.0", "< 4.0"
+  spec.add_dependency "good_job", ">= 3.0", "< 5.0"
 end
diff --git a/judoscale-good_job/lib/judoscale/good_job/metrics_collector.rb b/judoscale-good_job/lib/judoscale/good_job/metrics_collector.rb
index c64812f9..8731f875 100644
--- a/judoscale-good_job/lib/judoscale/good_job/metrics_collector.rb
+++ b/judoscale-good_job/lib/judoscale/good_job/metrics_collector.rb
@@ -9,19 +9,29 @@ module GoodJob
     class MetricsCollector < Judoscale::JobMetricsCollector
       include ActiveRecordHelper
 
+      def self.good_job_v4?
+        Gem::Version.new(::GoodJob::VERSION) >= Gem::Version.new("4")
+      end
+
+      def self.good_job_base_class
+        good_job_v4? ? ::GoodJob::Job : ::GoodJob::Execution
+      end
+
       def self.adapter_config
         Judoscale::Config.instance.good_job
       end
 
       def self.collect?(config)
-        super && ActiveRecordHelper.table_exists_for_model?(::GoodJob::Execution)
+        super && ActiveRecordHelper.table_exists_for_model?(good_job_base_class)
       end
 
       def initialize
         super
 
+        @good_job_base_class = self.class.good_job_base_class
+
         queue_names = run_silently do
-          ::GoodJob::Execution.select("distinct queue_name").map(&:queue_name)
+          @good_job_base_class.select("distinct queue_name").map(&:queue_name)
         end
         self.queues |= queue_names
       end
@@ -32,7 +42,7 @@ def collect
 
         # logically we don't need the finished_at condition, but it lets postgres use the indexes
         oldest_execution_time_by_queue = run_silently do
-          ::GoodJob::Execution
+          @good_job_base_class
             .where(performed_at: nil, finished_at: nil)
             .group(:queue_name)
             .pluck(:queue_name, Arel.sql("min(coalesce(scheduled_at, created_at))"))
@@ -42,7 +52,7 @@ def collect
 
         if track_busy_jobs?
           busy_count_by_queue = run_silently do
-            ::GoodJob::Execution.running.group(:queue_name).count
+            @good_job_base_class.running.group(:queue_name).count
           end
           self.queues |= busy_count_by_queue.keys
         end
diff --git a/judoscale-good_job/test/metrics_collector_test.rb b/judoscale-good_job/test/metrics_collector_test.rb
index 38dab552..a9510fa9 100644
--- a/judoscale-good_job/test/metrics_collector_test.rb
+++ b/judoscale-good_job/test/metrics_collector_test.rb
@@ -143,9 +143,14 @@ def clear_enqueued_jobs
       it "tracks busy jobs when the configuration is enabled" do
         use_adapter_config :good_job, track_busy_jobs: true do
           Delayable.set(queue: "default").perform_later
-          ::GoodJob::Execution.last.update!(performed_at: Time.now.utc)
+          metrics = nil
+          ::GoodJob::JobPerformer.new("default").next do |execution|
+            # Support GoodJob v3 query/scope `GoodJob::Execution.running`, which filters by `performed_at`.
+            # v4 scope `GoodJob::Job.running` joins with the advisory lock created by `JobPerformer#next` instead.
+            execution.update!(performed_at: Time.now.utc)
 
-          metrics = subject.collect
+            metrics = subject.collect
+          end
 
           _(metrics.size).must_equal 2
           _(metrics[1].value).must_equal 1
@@ -158,9 +163,13 @@ def clear_enqueued_jobs
         use_config log_level: :debug do
           use_adapter_config :good_job, track_busy_jobs: true do
             Delayable.set(queue: "default").perform_later
-            ::GoodJob::Execution.last.update!(performed_at: Time.now.utc)
+            ::GoodJob::JobPerformer.new("default").next do |execution|
+              # Support GoodJob v3 query/scope `GoodJob::Execution.running`, which filters by `performed_at`.
+              # v4 scope `GoodJob::Job.running` joins with the advisory lock created by `JobPerformer#next` instead.
+              execution.update!(performed_at: Time.now.utc)
 
-            subject.collect
+              subject.collect
+            end
 
             _(log_string).must_match %r{good_job-qt.default=.+ good_job-busy.default=1}
           end
diff --git a/sample-apps/good_job-multi-db-sample/Gemfile.lock b/sample-apps/good_job-multi-db-sample/Gemfile.lock
index 13335f30..2d130533 100644
--- a/sample-apps/good_job-multi-db-sample/Gemfile.lock
+++ b/sample-apps/good_job-multi-db-sample/Gemfile.lock
@@ -1,21 +1,21 @@
 PATH
   remote: ../../judoscale-good_job
   specs:
-    judoscale-good_job (1.7.0)
-      good_job (>= 3.0, < 4.0)
-      judoscale-ruby (= 1.7.0)
+    judoscale-good_job (1.7.1)
+      good_job (>= 3.0, < 5.0)
+      judoscale-ruby (= 1.7.1)
 
 PATH
   remote: ../../judoscale-rails
   specs:
-    judoscale-rails (1.7.0)
-      judoscale-ruby (= 1.7.0)
+    judoscale-rails (1.7.1)
+      judoscale-ruby (= 1.7.1)
       railties
 
 PATH
   remote: ../../judoscale-ruby
   specs:
-    judoscale-ruby (1.7.0)
+    judoscale-ruby (1.7.1)
 
 GEM
   remote: https://rubygems.org/
diff --git a/sample-apps/good_job-multi-db-sample/app/views/jobs/index.html.erb b/sample-apps/good_job-multi-db-sample/app/views/jobs/index.html.erb
index f2ec0474..41e2f7db 100644
--- a/sample-apps/good_job-multi-db-sample/app/views/jobs/index.html.erb
+++ b/sample-apps/good_job-multi-db-sample/app/views/jobs/index.html.erb
@@ -1,4 +1,4 @@
-<h1>Judoscale: GoodJob Sample</h1>
+<h1>Judoscale: GoodJob MultiDB Sample</h1>
 
 <p>
   Judoscale is reporting metrics to <a href="https://judoscale-adapter-mock.requestcatcher.com" target="_blank" rel="noreferrer">https://judoscale-adapter-mock.requestcatcher.com</a>.
diff --git a/sample-apps/good_job-multi-db-sample/app/views/layouts/application.html.erb b/sample-apps/good_job-multi-db-sample/app/views/layouts/application.html.erb
index 252663a2..274e4f93 100644
--- a/sample-apps/good_job-multi-db-sample/app/views/layouts/application.html.erb
+++ b/sample-apps/good_job-multi-db-sample/app/views/layouts/application.html.erb
@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <html>
   <head>
-    <title>Judoscale: GoodJob Sample</title>
+    <title>Judoscale: GoodJob MultiDB Sample</title>
     <meta name="viewport" content="width=device-width,initial-scale=1">
     <%= csrf_meta_tags %>
     <%= csp_meta_tag %>
diff --git a/sample-apps/good_job-sample/Gemfile b/sample-apps/good_job-sample/Gemfile
index ed11b95e..4fd015ce 100644
--- a/sample-apps/good_job-sample/Gemfile
+++ b/sample-apps/good_job-sample/Gemfile
@@ -15,4 +15,4 @@ gem "judoscale-ruby", path: "../../judoscale-ruby"
 gem "judoscale-rails", path: "../../judoscale-rails"
 gem "judoscale-good_job", path: "../../judoscale-good_job"
 
-gem "good_job", "~> 3.7"
+gem "good_job", "~> 4.0"
diff --git a/sample-apps/good_job-sample/Gemfile.lock b/sample-apps/good_job-sample/Gemfile.lock
index a9ecc936..39ccb707 100644
--- a/sample-apps/good_job-sample/Gemfile.lock
+++ b/sample-apps/good_job-sample/Gemfile.lock
@@ -1,21 +1,21 @@
 PATH
   remote: ../../judoscale-good_job
   specs:
-    judoscale-good_job (1.7.0)
-      good_job (>= 3.0, < 4.0)
-      judoscale-ruby (= 1.7.0)
+    judoscale-good_job (1.7.1)
+      good_job (>= 3.0, < 5.0)
+      judoscale-ruby (= 1.7.1)
 
 PATH
   remote: ../../judoscale-rails
   specs:
-    judoscale-rails (1.7.0)
-      judoscale-ruby (= 1.7.0)
+    judoscale-rails (1.7.1)
+      judoscale-ruby (= 1.7.1)
       railties
 
 PATH
   remote: ../../judoscale-ruby
   specs:
-    judoscale-ruby (1.7.0)
+    judoscale-ruby (1.7.1)
 
 GEM
   remote: https://rubygems.org/
@@ -57,13 +57,13 @@ GEM
       raabro (~> 1.4)
     globalid (1.2.1)
       activesupport (>= 6.1)
-    good_job (3.99.0)
-      activejob (>= 6.0.0)
-      activerecord (>= 6.0.0)
-      concurrent-ruby (>= 1.0.2)
-      fugit (>= 1.1)
-      railties (>= 6.0.0)
-      thor (>= 0.14.1)
+    good_job (4.0.1)
+      activejob (>= 6.1.0)
+      activerecord (>= 6.1.0)
+      concurrent-ruby (>= 1.3.1)
+      fugit (>= 1.11.0)
+      railties (>= 6.1.0)
+      thor (>= 1.0.0)
     i18n (1.14.5)
       concurrent-ruby (~> 1.0)
     loofah (2.22.0)
@@ -119,7 +119,7 @@ DEPENDENCIES
   activejob (~> 7.0.1)
   activemodel (~> 7.0.1)
   activerecord (~> 7.0.1)
-  good_job (~> 3.7)
+  good_job (~> 4.0)
   judoscale-good_job!
   judoscale-rails!
   judoscale-ruby!