diff --git a/activejob/CHANGELOG.md b/activejob/CHANGELOG.md
index 5a0f372c8db8a..53e51e5222655 100644
--- a/activejob/CHANGELOG.md
+++ b/activejob/CHANGELOG.md
@@ -1,3 +1,10 @@
+*   Set `scheduled_at` attribute as a Time object instead of epoch seconds, and serialize and deserialize the value
+    when enqueued. Assigning a numeric/epoch value to scheduled_at= is deprecated; use a Time object instead.
+
+    Deserializes `enqueued_at` as a Time instead of ISO8601 String.
+
+    *Ben Sheldon*
+
 *   Clarify the backoff strategy for the recommended `:wait` option when retrying jobs
 
     `wait: :exponentially_longer` is waiting polynomially longer, so it is now recommended to use `wait: :polynomially_longer` to keep the same behavior.
diff --git a/activejob/lib/active_job/core.rb b/activejob/lib/active_job/core.rb
index 1743327486391..3a6c4cd280fbc 100644
--- a/activejob/lib/active_job/core.rb
+++ b/activejob/lib/active_job/core.rb
@@ -12,8 +12,10 @@ module Core
     attr_accessor :arguments
     attr_writer :serialized_arguments
 
-    # Timestamp when the job should be performed
-    attr_accessor :scheduled_at
+    # Time when the job should be performed
+    attr_reader :scheduled_at
+
+    attr_reader :_scheduled_at_time # :nodoc:
 
     # Job Identifier
     attr_accessor :job_id
@@ -94,6 +96,8 @@ def initialize(*arguments)
       @arguments  = arguments
       @job_id     = SecureRandom.uuid
       @queue_name = self.class.queue_name
+      @scheduled_at = nil
+      @_scheduled_at_time = nil
       @priority   = self.class.priority
       @executions = 0
       @exception_executions = {}
@@ -115,7 +119,8 @@ def serialize
         "exception_executions" => exception_executions,
         "locale"     => I18n.locale.to_s,
         "timezone"   => timezone,
-        "enqueued_at" => Time.now.utc.iso8601(9)
+        "enqueued_at" => Time.now.utc.iso8601(9),
+        "scheduled_at" => _scheduled_at_time ? _scheduled_at_time.utc.iso8601(9) : nil,
       }
     end
 
@@ -155,19 +160,32 @@ def deserialize(job_data)
       self.exception_executions = job_data["exception_executions"]
       self.locale               = job_data["locale"] || I18n.locale.to_s
       self.timezone             = job_data["timezone"] || Time.zone&.name
-      self.enqueued_at          = job_data["enqueued_at"]
+      self.enqueued_at          = Time.iso8601(job_data["enqueued_at"]) if job_data["enqueued_at"]
+      self.scheduled_at         = Time.iso8601(job_data["scheduled_at"]) if job_data["scheduled_at"]
     end
 
     # Configures the job with the given options.
     def set(options = {}) # :nodoc:
-      self.scheduled_at = options[:wait].seconds.from_now.to_f if options[:wait]
-      self.scheduled_at = options[:wait_until].to_f if options[:wait_until]
+      self.scheduled_at = options[:wait].seconds.from_now if options[:wait]
+      self.scheduled_at = options[:wait_until] if options[:wait_until]
       self.queue_name   = self.class.queue_name_from_part(options[:queue]) if options[:queue]
       self.priority     = options[:priority].to_i if options[:priority]
 
       self
     end
 
+    def scheduled_at=(value)
+      @_scheduled_at_time = if value&.is_a?(Numeric)
+        ActiveJob.deprecator.warn(<<~MSG.squish)
+          Assigning a numeric/epoch value to scheduled_at is deprecated. Use a Time object instead.
+        MSG
+        Time.at(value)
+      else
+        value
+      end
+      @scheduled_at = value
+    end
+
     private
       def serialize_arguments_if_needed(arguments)
         if arguments_serialized?
diff --git a/activejob/lib/active_job/enqueuing.rb b/activejob/lib/active_job/enqueuing.rb
index 357dcd71d0e7b..a805a53f62c3d 100644
--- a/activejob/lib/active_job/enqueuing.rb
+++ b/activejob/lib/active_job/enqueuing.rb
@@ -23,7 +23,7 @@ def perform_all_later(*jobs)
             adapter_jobs.each do |job|
               job.successfully_enqueued = false
               if job.scheduled_at
-                queue_adapter.enqueue_at(job, job.scheduled_at)
+                queue_adapter.enqueue_at(job, job._scheduled_at_time.to_f)
               else
                 queue_adapter.enqueue(job)
               end
@@ -92,7 +92,7 @@ def enqueue(options = {})
 
       run_callbacks :enqueue do
         if scheduled_at
-          queue_adapter.enqueue_at self, scheduled_at
+          queue_adapter.enqueue_at self, _scheduled_at_time.to_f
         else
           queue_adapter.enqueue self
         end
diff --git a/activejob/lib/active_job/log_subscriber.rb b/activejob/lib/active_job/log_subscriber.rb
index 0d39048b3a965..5982fe3ef2441 100644
--- a/activejob/lib/active_job/log_subscriber.rb
+++ b/activejob/lib/active_job/log_subscriber.rb
@@ -76,7 +76,7 @@ def enqueue_all(event)
     def perform_start(event)
       info do
         job = event.payload[:job]
-        "Performing #{job.class.name} (Job ID: #{job.job_id}) from #{queue_name(event)} enqueued at #{job.enqueued_at}" + args_info(job)
+        "Performing #{job.class.name} (Job ID: #{job.job_id}) from #{queue_name(event)} enqueued at #{job.enqueued_at.utc.iso8601(9)}" + args_info(job)
       end
     end
     subscribe_log_level :perform_start, :info
diff --git a/activejob/lib/active_job/queue_adapters/sidekiq_adapter.rb b/activejob/lib/active_job/queue_adapters/sidekiq_adapter.rb
index 9cf90b38f849a..55b578ae7cd63 100644
--- a/activejob/lib/active_job/queue_adapters/sidekiq_adapter.rb
+++ b/activejob/lib/active_job/queue_adapters/sidekiq_adapter.rb
@@ -54,7 +54,7 @@ def enqueue_all(jobs) # :nodoc:
                 "wrapped" => job_class,
                 "queue" => queue,
                 "args" => scheduled_jobs.map { |job| [job.serialize] },
-                "at" => scheduled_jobs.map { |job| job.scheduled_at }
+                "at" => scheduled_jobs.map { |job| job.scheduled_at&.to_f }
               )
               enqueued_count += jids.compact.size
             end
diff --git a/activejob/lib/active_job/queue_adapters/test_adapter.rb b/activejob/lib/active_job/queue_adapters/test_adapter.rb
index 975ba9a7dfbb5..6e1c8ec6a2bbc 100644
--- a/activejob/lib/active_job/queue_adapters/test_adapter.rb
+++ b/activejob/lib/active_job/queue_adapters/test_adapter.rb
@@ -59,7 +59,7 @@ def filtered?(job)
         end
 
         def filtered_time?(job)
-          job.scheduled_at > at.to_f if at && job.scheduled_at
+          job.scheduled_at > at if at && job.scheduled_at
         end
 
         def filtered_queue?(job)
diff --git a/activejob/lib/active_job/test_helper.rb b/activejob/lib/active_job/test_helper.rb
index aee3fb7a9c160..149fc8a47c4b1 100644
--- a/activejob/lib/active_job/test_helper.rb
+++ b/activejob/lib/active_job/test_helper.rb
@@ -730,7 +730,7 @@ def deserialize_args_for_assertion(job)
 
       def instantiate_job(payload, skip_deserialize_arguments: false)
         job = payload[:job].deserialize(payload)
-        job.scheduled_at = payload[:at].to_f if payload.key?(:at)
+        job.scheduled_at = payload[:at] if payload.key?(:at)
         job.send(:deserialize_arguments_if_needed) unless skip_deserialize_arguments
         job
       end
diff --git a/activejob/test/cases/job_serialization_test.rb b/activejob/test/cases/job_serialization_test.rb
index 4cf90412ac25b..f2b98958cdb5d 100644
--- a/activejob/test/cases/job_serialization_test.rb
+++ b/activejob/test/cases/job_serialization_test.rb
@@ -65,13 +65,50 @@ class JobSerializationTest < ActiveSupport::TestCase
     end
   end
 
-  test "serializes enqueued_at with full precision" do
+  test "serializes and deserializes enqueued_at with full precision" do
     freeze_time
 
     serialized = HelloJob.new.serialize
     assert_kind_of String, serialized["enqueued_at"]
 
     enqueued_at = HelloJob.deserialize(serialized).enqueued_at
-    assert_equal Time.now.utc, Time.iso8601(enqueued_at)
+    assert_kind_of Time, enqueued_at
+    assert_equal Time.now.utc, enqueued_at
+  end
+
+  test "serializes and deserializes scheduled_at as Time" do
+    freeze_time
+    current_time = Time.now
+
+    job = HelloJob.new
+    job.scheduled_at = current_time
+    serialized_job = job.serialize
+    assert_kind_of String, serialized_job["enqueued_at"]
+    assert_equal current_time.utc.iso8601(9), serialized_job["enqueued_at"]
+
+    deserialized_job = HelloJob.new
+    deserialized_job.deserialize(serialized_job)
+    assert_equal current_time, deserialized_job.scheduled_at
+
+    assert_equal job.serialize, deserialized_job.serialize
+  end
+
+  test "deprecates and coerces numerical scheduled_at attribute to Time when serialized and deserialized" do
+    freeze_time
+    current_time = Time.now
+
+    job = HelloJob.new
+    assert_deprecated(ActiveJob.deprecator) do
+      job.scheduled_at = current_time.to_f
+    end
+
+    serialized_job = job.serialize
+    assert_kind_of String, serialized_job["scheduled_at"]
+    assert_equal current_time.utc.iso8601(9), serialized_job["scheduled_at"]
+
+    deserialized_job = HelloJob.new
+    deserialized_job.deserialize(serialized_job)
+    assert_equal current_time, deserialized_job.scheduled_at
+    assert_equal job.serialize, deserialized_job.serialize
   end
 end
diff --git a/activejob/test/cases/queuing_test.rb b/activejob/test/cases/queuing_test.rb
index 675496cbcb82a..2413987df33eb 100644
--- a/activejob/test/cases/queuing_test.rb
+++ b/activejob/test/cases/queuing_test.rb
@@ -5,6 +5,7 @@
 require "jobs/enqueue_error_job"
 require "jobs/multiple_kwargs_job"
 require "active_support/core_ext/numeric/time"
+require "minitest/mock"
 
 class QueuingTest < ActiveSupport::TestCase
   setup do
@@ -35,7 +36,7 @@ class QueuingTest < ActiveSupport::TestCase
 
   test "job returned by perform_at has the timestamp available" do
     job = HelloJob.set(wait_until: Time.utc(2014, 1, 1)).perform_later
-    assert_equal Time.utc(2014, 1, 1).to_f, job.scheduled_at
+    assert_equal Time.utc(2014, 1, 1), job.scheduled_at
   rescue NotImplementedError
     skip
   end
@@ -71,6 +72,19 @@ class QueuingTest < ActiveSupport::TestCase
     assert_equal ["Jamie says hello", "Job with argument1: John, argument2: 42"], JobBuffer.values.sort
   end
 
+  test "perform_all_later enqueues jobs with schedules" do
+    scheduled_job_1 = HelloJob.new("Scheduled 2014")
+    scheduled_job_1.set(wait_until: Time.utc(2014, 1, 1))
+
+    scheduled_job_2 = HelloJob.new("Scheduled 2015")
+    scheduled_job_2.scheduled_at = Time.utc(2015, 1, 1)
+
+    ActiveJob.perform_all_later(scheduled_job_1, scheduled_job_2)
+    assert_equal ["Scheduled 2014 says hello", "Scheduled 2015 says hello"], JobBuffer.values.sort
+  rescue NotImplementedError
+    skip
+  end
+
   test "perform_all_later instrumentation" do
     jobs = HelloJob.new("Jamie"), HelloJob.new("John")
     called = false
diff --git a/activejob/test/jobs/retry_job.rb b/activejob/test/jobs/retry_job.rb
index 33a415c471f90..a1b5a0f13ef08 100644
--- a/activejob/test/jobs/retry_job.rb
+++ b/activejob/test/jobs/retry_job.rb
@@ -38,7 +38,7 @@ class RetryJob < ActiveJob::Base
 
   before_enqueue do |job|
     if job.arguments.include?(:log_scheduled_at) && job.scheduled_at
-      JobBuffer.add("Next execution scheduled at #{job.scheduled_at}")
+      JobBuffer.add("Next execution scheduled at #{job.scheduled_at.to_f}")
     end
   end