Background: Patients’ web-based access to their medical records is expected to promote their role and responsibility in managing their own health and treatments and supporting shared decision-making. As of July 2020, general practices in the Netherlands are legally obliged to provide their patients access to their electronic medical records. Web-based access provision is facilitated and stimulated through a national support program named OPEN. Objective: We aimed to investigate general practice staff experiences with providing web-based access; investigate its impact on patient consultations, administrative actions, and patient inquiries; and investigate how it affects routine general practice workflow processes. Methods: In October 2021, a total of 3813 general practices in the Netherlands were invited to complete a web-based survey that included questions regarding their experiences with the provision of web-based access to medical records and how it affects routine general practice workflow. Responses of general practices that started providing web-based access before 2020, in 2020, or in 2021 were analyzed to identify trends. Results: Of 3813 invited general practices, 523 (13.72%) completed the survey. Approximately all responding general practices (487/523, 93.1%) indicated that they provide web-based access. Experiences with patients’ web-based access were diverse, with 36.9% (178/482) primarily positive, 8.1% (39/482) primarily negative, 42.3% (204/482) neutral, and 12.7% (61/482) could not (yet) indicate how they experienced web-based access. Of the total, two-thirds (311/473, 65.8%) reported an increase in e-consultations and a similar percentage (302/474, 63.7%) indicated an increase in administrative actions associated with web-based access provision. A small proportion of the practices (≤10%) experienced a decrease in patient contacts. Earlier adoption of web-based access was associated with a more positive attitude toward web-based access and more positive experienced effects related to patient ...