Monica Spear, 29, and Henry Thomas Berry, 39, were slain late Monday night on a roadside near Puerto Cabello after their car broke down, authorities said in a statement Tuesday.
The statement said the couple's daughter was in stable condition after receiving medical attention for unspecified injuries. According to local media reports, Spear and Berry had a good relationship despite being divorced, and they were waiting for a tow truck at the time of the attack.
Venezuela has one of the world's highest murder rates. Violent crime is so rampant that people tend to stay home after dark.
Spear's death set off a wave of anger on social media directed at the populist government's poor record on crime.
According to the nonprofit Venezuelan Observatory of Violence, the South American country's murder rate was 79 per 100,000 inhabitants last year. Government statistics put the rate lower.
Spear was crowned Miss Venezuela in 2004. She acted in numerous soap operas for the U.S.-based Telemundo network, most recently "Pasion Prohibida."
She split her time between Venezuela and the United States and was on vacation when she was killed.
The Associated Press contributed to this report.