A man came up behind the 27-year-old as she walked into Glasgow Green from Saltmarket, pushed her to the ground and carried out the assault.
She struggled with her attacker, who then let go and fled the scene.
The woman did not need hospital treatment but was left badly shaken by the incident.
Police Scotland appealed for information about the attack, which happened at around 11.30pm on Saturday April 19. Detective Inspector Diane Caldwell said: "This was an extremely upsetting and frightening ordeal that this woman experienced.
"A forensic examination is taking place at the area where this attack took place within the park.
"Detectives are alsocarrying out further inquiries in the local area and gathering CCTV footage in an effort to gather more information about the man responsible. It is vital that we trace this man, and I would urge anyone who may have been in the park and witnessed this assault take place, or who may have seen him acting suspiciously or running through the park, to contact police as a matter of urgency."
The man is described as white, about 5ft 8in tall, with short dark hair.