The man is under police guard in hospital.
The incident took place on Thursday at the couple’s home in Nelspruit.
Provincial police spokesperson Brigadier Leonard Hlathi said the husband, 42, arrived home from work and asked to speak to his wife, 39.
“They stepped outside for a brief discussion, but the husband went back into the house and allegedly fatally shot his wife and shot and wounded himself.
“Police and medical personnel were notified about the incident and they responded swiftly. The woman was unfortunately certified dead by paramedics at the scene, while the husband was rushed to hospital where he is under police guard,” said Hlathi.
Mpumalanga police commissioner Lieutenant-General Mondli Zuma condemned the incident.
He pleaded with members of the community to refrain from using violence to resolve domestic issues.
“People should stop perpetuating domestic violence against women and children. They should evade violence by consulting social workers, traditional leaders and other relevant structures to intervene and resolve their problems amicably,” said Zuma.