According to police, Professor Dr Akbar Cheema was travelling in his car when armed suspects intercepted him near Kalma Chowk and fatally shot him.
The suspects fired four bullets at the professor, three of which hit him in the leg while one pierced his chest, police said.
The suspects, who were on a motorcycle, fled the scene after the shooting.
Earlier reports had suggested that the professor was shot dead while resisting an armed robbery.
However, evidence now indicates that the incident was motivated by personal enmity, police said.
Dr Cheema was a professor at the GCU’s Botany Department.
Police transferred the deceased professor’s body to hospital for post-mortem and have launched an investigation into the incident.
Punjab Chief Minister Shehbaz Sharif has summoned a report on the incident from CCPO Lahore and directed authorities to arrest the culprits at the earliest.