People are taking to Twitter to share the reasons why they're voting today.
It's the battle for London mayor and fight for control of the Scottish parliament, as well as council elections across England, Welsh Assembly and Northern Ireland Assembly.
And if you're wondering whether you can really be bothered to head to your local polling station and cast your vote, these reasons might change your mind.
1. Because the right to vote was a hard won struggle.
2. Particularly for women.
3. Your vote actually does make a difference.
4. Not every country around the world has a free, fair voting system like we do.
5. Because otherwise you can't really complain about those in power.
6. Because a minority shouldn't be able to decide.
7. To stop someone you really don't want as London Mayor.
8. or if you particularly want (or don't want) to see this happen.
9. Because it's a lovely day anyway, so you may as well.
10. And it really doesn't take very long.
11. And then you can take a nice selfie for your followers and encourage them to vote too.
12. And there might be a touch of comedy along the way.