Three members of the League One club have been suspended after a video on social media revealed the footballers inhaling nitrous oxide (also known as 'laughing gas') and smoking a shisha pipe.
The video was published a day after Swindon's 2-0 defeat at Oldham on Tuesday.
The club statement read, "The club have already started an internal investigation into the trio's recent conduct and they will not be considered for selection during this process.
"Swindon Town will be making no further comment until the investigation is complete."