diff --git a/app/models/issue.rb b/app/models/issue.rb
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -1750,12 +1750,12 @@ class Issue < ActiveRecord::Base
 
     unless @copied_from.leaf? || @copy_options[:subtasks] == false
       copy_options = (@copy_options || {}).merge(:subtasks => false)
-      copied_issue_ids = {@copied_from.id => self.id}
+      copied_issues = {@copied_from.id => self}
       @copied_from.reload.descendants.reorder("#{Issue.table_name}.lft").each do |child|
         # Do not copy self when copying an issue as a descendant of the copied issue
         next if child == self
         # Do not copy subtasks of issues that were not copied
-        next unless copied_issue_ids[child.parent_id]
+        next unless copied_issues[child.parent_id]
 
         # Do not copy subtasks that are not visible to avoid potential disclosure of private data
         unless child.visible?
           if logger
diff --git a/app/models/issue.rb b/app/models/issue.rb
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -1773,25 +1773,40 @@ class Issue < ActiveRecord::Base
         end
         copy.author = author
         copy.project = project
-        copy.parent_issue_id = copied_issue_ids[child.parent_id]
+        copy.parent_issue_id = copied_issues[child.parent_id].id
         unless child.fixed_version.present? && child.fixed_version.status == 'open'
           copy.fixed_version_id = nil
         end
         unless child.assigned_to_id.present? &&
                  child.assigned_to.status == User::STATUS_ACTIVE
           copy.assigned_to = nil
         end
         unless copy.save
           if logger
             logger.error(
               "Could not copy subtask ##{child.id} " \
                 "while copying ##{@copied_from.id} to ##{id} due to validation errors: " \
                 "#{copy.errors.full_messages.join(', ')}"
             )
           end
           next
         end
-        copied_issue_ids[child.id] = copy.id
+        copied_issues[child.id] = copy
+      end
+
+      # Replicate dependencies between copied children
+      @copied_from.reload.descendants.reorder("#{Issue.table_name}.lft").each do |child|
+        copy = copied_issues[child.id]
+        next unless copy
+        child.relations_to.each do |rel|
+          next unless copied_issues.key?(rel.issue_from.id)
+          from = Issue.find_by_id(copied_issues[rel.issue_from.id].id)
+          next unless from
+          relation = IssueRelation.new(:issue_from => from, :issue_to => copy, :relation_type => rel.relation_type)
+          unless relation.save
+            logger.error "Could not create relation while copying ##{child.id} to ##{copy.id} due to validation errors: #{relation.errors.full_messages.join(', ')}" if logger
+          end
+        end
       end
     end
     @after_create_from_copy_handled = true