Yes, KMSPico can be used to activate both Windows 10 and Windows 11. The tool is designed to work with various versions of Windows, particularly those that support KMS activation. However, success rates may vary based on the specific build and updates of Windows. It’s important to keep in mind that while KMSPico may activate your Windows system, it does not provide long-term security or support from Microsoft. Frequent updates or system changes may prompt reactivation, which can complicate your experience.