ABSTRACT: Limited evidence exists on salary differences between male and female academic physicians, largely owing to difficulty obtaining data on salary and factors influencing salary. Existing studies have been limited by reliance on survey-based approaches to measuring sex differences in earnings, lack of contemporary data, small sample sizes, or limited geographic representation.To analyze sex differences in earnings among US academic physicians.Freedom of Information laws mandate release of salary information of public university employees in several states. In 12 states with salary information published online, salary data were extracted on 10?241 academic physicians at 24 public medical schools. These data were linked to a unique physician database with detailed information on sex, age, years of experience, faculty rank, specialty, scientific authorship, National Institutes of Health funding, clinical trial participation, and Medicare reimbursements (proxy for clinical revenue). Sex differences in salary were estimated after adjusting for these factors.Physician sex.Annual salary.Among 10?241 physicians, female physicians (n?=?3549) had lower mean (SD) unadjusted salaries than male physicians ($206?641 [$88?238] vs $257?957 [$137?202]; absolute difference, $51?315 [95% CI, $46?330-$56?301]). Sex differences persisted after multivariable adjustment ($227?783 [95% CI, $224?117-$231?448] vs $247?661 [95% CI, $245?065-$250?258] with an absolute difference of $19?878 [95% CI, $15?261-$24?495]). Sex differences in salary varied across specialties, institutions, and faculty ranks. For example, adjusted salaries of female full professors ($250 971 [95% CI, $242 307-$259 635]) were comparable to those of male associate professors ($247?212 [95% CI, $241?850-$252?575]). Among specialties, adjusted salaries were highest in orthopedic surgery ($358?093 [95% CI, $344?354-$371?831]), surgical subspecialties ($318?760 [95% CI, $311?030-$326?491]), and general surgery ($302?666 [95% CI, $294?060-$311?272]) and lowest in infectious disease, family medicine, and neurology (mean income, <$200?000). Years of experience, total publications, clinical trial participation, and Medicare payments were positively associated with salary.Among physicians with faculty appointments at 24 US public medical schools, significant sex differences in salary exist even after accounting for age, experience, specialty, faculty rank, and measures of research productivity and clinical revenue.