Sure! There are people who live on the international space station for 6 months at a time. They can’t live up there permanently though, they need supplies to keep them going. Also, us humans aren’t evolved to live in zero gravity, so over time astronauts get weaker and are more likely to get sick. Some science fiction books talk about us evolving in the future to adapt to space. If that went on for long enough, we could even split into two different species, space people and Earth people!
Grant Kennedy answered on 19 Mar 2013: http://spacem13.imascientist.org.uk/2013/03/19/is-it-possible-for-someone-to-live-in-space/