When finishing basement walls do you need a vapor barier between the metal studs and drywall ? Is it ok not to?

To prevent a mold problem you need to put up the vapor barier before you put the metal studs in place. You should also put insulation between the studs, this will also help protect your drywall and any paint you use. If you don't it right you will be repeting your project in a short time. Good luck!