Can you get your car inspected without a valid registration?
Like many things in Massachusetts, there's a set order. Of course this holds true with registration and inspection of your car.
Unfortunately, you won't be able to get an inspection if you do not have a valid registration on your car. So be prepared to spend some time at the RMV if the inspection sticker on your windshield is getting really close to being expired.
The good news is that you have a ton of options when you register your car. The valid timeframe for registration is all tied to the type of plate that you put on your car. If you want a special plate, you'll have to re-register every year (at a higher cost), whereas the "normal" plates are good for a solid two years. Motorcycles have to renew every year in Massachusetts, but the plates are only $20. You can get a full breakdown on plate fees and the registration process over on the RMV website.
If your car is already registered in Massachusetts, be sure to watch your mail a few months before expiration. You'll get a nice little notice telling you when you're registration will be expiring, and it will also give you a bunch of options for paying the fees that are due. My favorite is just paying online, but you can also mail in your payment, or even go to a full-service RMV branch to get squared away.
If you've got a newly registered vehicle, hurry up and get your inspection taken care of ASAP. Technically speaking, you only have a 7 days to get your inspection before you are breaking the law.