The single vehicle collision occurred on the Mallow road side of the Lissivigeen junction shortly after 6pm.
A woman who was injured in the incident was brought by air ambulance to hospital; a man was also transferred to hospital by ambulance.
The main Killarney Rathmore road was closed for several hours last night for a forensic examination.
The main Cork Killarney road was also completely closed for a time last evening to facilitate the air ambulance landing.
Killarney Gardaí are investigating the crash and are appealing for any witnesses to come forward.