Background: Self-tests enable the identification of (risk factors for) diseases and are carried out on the user's initiative without medical indication or advice and often unaided by a health professional. They are frequently used, and their availability and usage are expected to grow. Self-testing has both advantages and disadvantages. Making a well-informed decision about whether to self-test and which self-test to use is of major importance. Objective: To provide insights into the experiences of self-test users, identifying reasons to self-test and perceived (dis)advantages of using self-tests and the information highlighted as relevant by self-test users to make well-informed decisions. Methods: In a qualitative study, 28 users of a wide variety of self-tests shared their experiences in focus groups and interviews. Results: Perceived disadvantages of self-testing included the following: a wide range of available self-tests, lack of insights into their reliability and content, possibility of mistakes in administering them, possibility of false-positive and false-negative results, lack of clarity about how to interpret results and consequently what action to take and fear of not being taken seriously by a general practitioner. Self-test aspects that were viewed as most important include informed decision making, user-friendliness, usefulness and reliability of results. Conclusion: A decision aid for future self-test users can help people make a deliberate decision on whether to use a self-test and which particular self-test to use from the wide range available. The government, health professionals, patient organizations, consumer organizations and citizens all have a role to play in the development and implementation of a decision aid.