Aside from the few countries that have restricted or outright banned them (including Belarus, China, Iran, Iraq, North Korea, Oman, Russia, Turkey, Turkmenistan, and the United Arab Emirates), VPNs are perfectly legal in most of the world. But keep in mind that illegal activities like torrenting copyrighted material, buying prohibited goods, and hacking are still illegal even with a VPN. Let's not get too brazen, here. Along those same lines, using a VPN to unblock streaming services from a country where it's not available isn't technically against the law, but it is a violation of the company's terms of use — i.e., you may get slapped with a warning, IP ban, or error message if caught.