Yes, you can enter Switzerland with a valid Schengen visa issued by Italy, provided you follow the "Main Destination" rule. Under the Schengen Agreement, you should apply for your visa from the country that is your primary destination (where you will spend the most time) or your first point of entry if you are visiting multiple countries for equal amounts of time. Once you have entered the Schengen Area through Italy and received your entry stamp, you can travel freely across the border into Switzerland without any further passport checks, as Switzerland is a member of the Schengen Area despite not being in the EU. In 2026, it is a recommended practice to carry proof of your travel itinerary, such as hotel bookings in both Italy and Switzerland, as border officials still conduct occasional "spot checks" to ensure travelers aren't "visa shopping" (applying at an easier embassy to bypass a harder one). If your Italian visa is a "Single Entry" visa, make sure you do not leave the Schengen Area (e.g., by flying to the UK or Turkey) before entering Switzerland, or your visa will become invalid for re-entry.