Houston residents, City of Bellaire residents and people in certain districts of HISD are eligible to vote in the run-off election.
Harris County Deputy Clerk Kevin Mausey says people need to remember there are different rules for election day than in the early voting period.
"We have a total of 410 polling locations. You will need to vote in the location that's assigned to your voting precinct. So a good thing to do is to check to see where exactly that location is before you leave to go to the poll. They can find those locations on our website at HarrisVotes.com."
Even if you didn't vote in the November general election, you can still vote in the run-off as long as you're registered.
There are a total of 11 races in the run-off, but depending on where you live you'll probably only see four or five on your ballot.
Laurie Johnson. KUHF-Houston Public Radio News.