In this article, we'll guide you through the essentials of writing a resignation letter when going back to school, ensuring you leave on good terms. You don't have to send your resignation letter 30 days before the start of the school year, you have to send it 30 days before your planned last day.Fill out the form on this page to get a free editable Google Docs template with sample teacher resignation letters to help you compose your own. In the opening paragraph, clearly state that you are resigning from your position. A resignation letter should be written at least 30 days prior to the effective date of resignation. The resignation letter should indicate the effective date of the resignation, which is the last day of work in the office. Add contact details, company name, and date. Learn some of my top tips for keeping it short and professional. You'll even find some templates you can plug into your very own teacher resignation letter. Resignation letters should use the formal greeting: "Dear".