Arrow And Flash Crossover Will Happen

Writer and Executive Producer Marc Guggenheim has confirmed that the Flash television series will crossover with Arrow. In an interview with Collider, Guggenheim was asked if he and his team were already considering a crossover. He said:

Well, we're fanboys and we always fantasize about, "Oh, we could do this cross-over.  We could do that episode."  Everything is always on the table.  I think it's one of the things that's made Arrow special.  But we also all collectively feel like The Flash needs to stand on its own two feet, now that it's gotten its launch from Arrow.  I would say, as with all things, we trust our instincts to know when is the right time.  Our compass has always just been our gut instinct.  When the time is right, it will happen.  Greg [Berlanti], Andrew [Kreisberg] and Geoff [Johns] have got to finish The Flash pilot first.  There are a bunch of things that have to happen before we can start cross-pollinating shows.

So, they might give The Flash a chance to get his feet planted first, but a crossover is definitely in the works somewhere down the line. Arrow airs Wednesday nights on the CW. The Flash pilot is currently in production.