diff --git a/app/models/issue.rb b/app/models/issue.rb
index 0a7cc5ed3..9dac7d9ca 100644
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -1849,6 +1849,24 @@ class Issue < ApplicationRecord
         end
         copied_issue_ids[child.id] = copy.id
       end
+
+      # Copy the relations between the copied subtasks
+      IssueRelation.where(:issue_from_id => copied_issue_ids.keys,
+                          :issue_to_id => copied_issue_ids.keys).each do |source_relation|
+        relation = IssueRelation.new
+        relation.attributes = source_relation.attributes.except('id', 'issue_from_id', 'issue_to_id')
+        relation.issue_from_id = copied_issue_ids[source_relation.issue_from_id]
+        relation.issue_to_id = copied_issue_ids[source_relation.issue_to_id]
+        unless relation.save
+          if logger
+            logger.error(
+              "Could not copy relation ##{source_relation.id} " \
+                "while copying ##{@copied_from.id} to ##{id} due to validation errors: " \
+                "#{relation.errors.full_messages.join(', ')}"
+            )
+          end
+        end
+      end
     end
     @after_create_from_copy_handled = true
   end
diff --git a/test/unit/issue_test.rb b/test/unit/issue_test.rb
index b22595c75..5755fcccc 100644
--- a/test/unit/issue_test.rb
+++ b/test/unit/issue_test.rb
@@ -1475,6 +1475,49 @@ class IssueTest < ActiveSupport::TestCase
     assert_equal copy.author, child_copy.author
   end
 
+  def test_copy_should_copy_relations_between_subtasks
+    parent = Issue.generate!
+    child1 = Issue.generate!(:parent_issue_id => parent.id, :subject => 'Child1')
+    child2 = Issue.generate!(:parent_issue_id => parent.id, :subject => 'Child2')
+    child21 = Issue.generate!(:parent_issue_id => child2.id, :subject => 'Child21')
+    other = Issue.generate!
+    IssueRelation.create!(:issue_from => child1, :issue_to => child2,
+                          :relation_type => IssueRelation::TYPE_PRECEDES, :delay => 2)
+    IssueRelation.create!(:issue_from => child1, :issue_to => child21,
+                          :relation_type => IssueRelation::TYPE_BLOCKS)
+    IssueRelation.create!(:issue_from => child1, :issue_to => other,
+                          :relation_type => IssueRelation::TYPE_RELATES)
+
+    copy = parent.reload.copy
+    copy.author = User.find(7)
+    # copied_to relations for the issue and its 3 subtasks, and the 2 relations between subtasks
+    assert_difference 'IssueRelation.count', 4 + 2 do
+      assert copy.save
+    end
+
+    copies = copy.reload.descendants.index_by(&:subject)
+    assert_equal [[copies['Child2'].id, IssueRelation::TYPE_PRECEDES, 2],
+                  [copies['Child21'].id, IssueRelation::TYPE_BLOCKS, nil]].sort_by(&:first),
+                 copies['Child1'].relations_from.map {|r| [r.issue_to_id, r.relation_type, r.delay]}.sort_by(&:first)
+    # Relations to issues outside of the copied subtree are not copied
+    assert_equal [child1.id], other.reload.relations.map(&:issue_from_id)
+  end
+
+  def test_copy_without_subtasks_should_not_copy_relations_between_subtasks
+    parent = Issue.generate!
+    child1 = Issue.generate!(:parent_issue_id => parent.id)
+    child2 = Issue.generate!(:parent_issue_id => parent.id)
+    IssueRelation.create!(:issue_from => child1, :issue_to => child2,
+                          :relation_type => IssueRelation::TYPE_PRECEDES)
+
+    copy = parent.reload.copy({}, :subtasks => false)
+    copy.author = User.find(7)
+    assert_difference 'IssueRelation.count', 1 do
+      assert copy.save
+    end
+    assert_empty copy.reload.descendants
+  end
+
   def test_copy_as_a_child_of_copied_issue_should_not_copy_itself
     parent = Issue.generate!
     child1 = Issue.generate!(:parent_issue_id => parent.id, :subject => 'Child 1')
-- 
2.43.0