Is It Legal to Download Facebook Videos?
The short version
Downloading a public video for your own private viewing is, in most places, treated very differently from republishing it. The act of saving a file is rarely the problem. What you then do with it usually is. This is a general explanation and not legal advice — rules vary by country, and if something matters commercially, ask a lawyer rather than a website.
Two separate things are involved
The first is copyright. Whoever made a video owns it from the moment it exists, whether or not they registered anything and whether or not the post says so. Being able to watch something publicly does not transfer any ownership to the viewer.
The second is Facebook's own terms of service, which are a contract between Facebook and its users rather than a law. Breaking terms is not a crime; it is grounds for Facebook to restrict an account. These are genuinely different kinds of obligation and are often confused.
What is usually fine
Saving a copy of a video you posted yourself. Keeping a public video to watch offline, without redistributing it. Archiving something you have been given permission to use. Downloading material that is genuinely in the public domain, or published under a licence that allows reuse.
What causes problems
Re-uploading someone else's video to your own page, channel or feed — with or without credit. Using a clip in anything commercial or advertising-supported without a licence. Removing or cropping out attribution. Redistributing music that came with the video: a track licensed for playback inside Facebook's apps is not licensed for a file on your computer, and automated systems detect this reliably.
Credit is not a licence
Adding "credit to the owner" does not make republishing lawful. It is a courtesy, not permission. Permission comes from the rights holder, and asking is easier than most people expect — creators frequently say yes when the request is specific and the credit is real.
If you are the rights holder
If your work is being used without permission, Facebook has a reporting process, and this site has a DMCA page explaining how to reach us and what we need in order to act on a request.