Short term solution : Lead by example, a good chance that they can learn from those and maybe copy them afterward. But the code quality will improve. This can take your time but as long as you have several good examples, you can reuse those. Long term solution: Encourage them to watch conference and good books like Clean Code, or TDD books. Those are incredibly good. Maybe they are not interested in at first, and never, but those who want to be better will become ones.