When properly stored, lasagna can last in the freezer for approximately 2 to 3 months. However, it's important to note that the quality and taste of the lasagna may start to deteriorate after the first month. To maximize the quality and flavor, it's recommended to consume the frozen lasagna within the first month. It's also a good practice to store the lasagna in an airtight container or wrap it tightly with aluminum foil or plastic wrap to prevent freezer burn.