Office Assistant salary at Ontario

The average office assistant salary at Ontario was $28,738 , which is 49 percent lower than the average salary for this job in California, and 31 percent lower than the national average for this job . Office Assistant salaries at Ontario typically range from $26,132 to $31,344 (25th to 75th percentile). The highest reported office assistant salary was $31,710. There are 5 employees at Ontario with the job title office assistant.