You need a high school diploma to be a game tester. There is no formal education requirement to be eligible to test games. However, completing either an associate's degree or a bachelor's degree would be very helpful for gaining employment in the field of game testing.
Typically, most game testers earn at least a bachelor's degree. The most common fields of study for someone wanting to become a game tester are computer science and software development. Other viable degree options are graphic design, business, or animation.
Game testing is a very competitive job market. Having a degree, specifically one in something like computer science, will make you more attractive to potential employers. Having a degree can also help with career advancement if you ever choose to enter the world of game development or design.
Another thing that employers tend to look for is that you have a genuine interest in video games. If you are a gamer who has a wide array of knowledge and experience with different games, this will also help make you more competitive when looking for a job.