|Portrayed by:||Louis Ferreira|
|First appearance:||A Danger to Himself and Others|
|Last appearance:||Goodnight, Mother|
|Occupation:||Doctor at Portland All Saints Hospital|
|Allies:||Dr. Porter (colleague)|
Doctor Guynan is a doctor who works at Portland All Saints Hospital. He informed Will Decody and Dylan Massett that Emma Decody was out of surgery and that it was a success. He later successfully detached her tube which allowed her to breathe unaided.