Starring: Katie Cassidy, David Ramsey, Stephen Amell, Colin Donnell, Emily Bett Rickards
Left Behind - S3-E10
Continuity mistake: In the previous episode Ra's al Ghul stabs Oliver through his chest, just below his left pec. When he pulls out the sword, a wound is visible. (However, seconds later, the wound is absent - different mistake). In this episode he is shown with a wound much lower (in his lower abdomen) and also later, with a bandage around his waist instead of his chest. (00:09:30 - 00:41:30)
The Magician - S3-E4
Revealing mistake: When Oliver meets Thea at the Grind and Jot Cafe (Which looks unsurprisingly like CC Jitters) you can see the cups on the table are from CC Jitters. (00:20:50)
Darkness on the Edge of Town - S1-E22
Oliver Queen: Roy! We haven't met. I'm Thea's disapproving older brother.
Trivia: When Barry and Oliver are fighting on the street, a police officer asks for backup and mentions Burton and Nolan street, as reference to Christopher Nolan and Tim Burton.