The average principal salary at London Isd was $76,369 , which is 26 percent lower than the average salary for this job in Texas, and 35 percent lower than the national average for this job . Principal salaries at London Isd typically range from $70,768 to $84,897 (25th to 75th percentile). The highest reported principal salary was $84,897. There are 3 employees at London Isd with the job title principal.