Great for employees stuck in this same position for too long, this resignation letter cites a lack of career growth.
Dear Mr./Ms. Bossname
I would like to tender my resignation letter as (position) from (company), effective (date).
I have always enjoyed my time and work with this company, and I am grateful to you as my (manager/supervisor) for your hard work and dedication. However, it has long been my career goal to expand my experience in (subject/field) and I will be seeking out opportunities that allow me to grow in that area.
Thank you for all your help over the past (amount of time), and good luck in the future.