Are you talking client or server?
Are you even talking database technology?
- 11g is just a marketing name
Did you try googling for Oracle on MAC?
Have you seen the MAC forum Oracle on Apple Mac OS X
Installation forum Installation
Client down load page
Oracle on MAC home page
If you are referring to the Oracle database, then the answer is no, since the last certified version was 10.2.0.4 on Leopard.
Please review lastest status of oracle db and Mac OS
Oracle Database on Unix AIX,HP-UX,Linux,Mac OS X,Solaris,Tru64 Unix Operating Systems Installation and Configuration Requirements Quick Reference (8.0.5 to 11.2) [ID 169706.1]
The latest Oracle Database release for Mac OS X is 184.108.40.206 ( 11gR2 ) . Its a client-only release and certified on Lion and Mountain Lion ( 10.8.2 ) . You can download the instant -client zip files from OTN.
Yes it can be installed on directly on the hardware ( non-virtualized ) environment ) , if that's what you mean .
Hope that helps .