An inspection report into the hospital found nursing staff on several wards had repeatedly to challenge medical staff to obey the strict rules over dress code and infection control.
Three different doctors were observed wearing a wristwatch, having long hair untied and wearing an outdoor jacket while at bedsides on the wards.
The inspectors have issued requirements to improve the Royal's performance in preventing hospital acquired infections.
The inspection team from Healthcare Improvement Scotland has given the hospital one month to ensure all staff stick to the dress code to ensure the risk of infection is minimised.
In all, it issued four requirements, including ensuring all patient equipment was stored and cleaned in one ward to reduce contamination risk, after three commodes and other equipment was found to be contaminated.
Rory Farrelly, NHS Greater Glasgow & Clyde acute director of nursing, said: "A plan has been developed to ensure the recommendations are implemented."