PURPOSE Authorship gender disparities persist across academic disciplines, including oncology. However, little is known about global variation in authorship gender distribution. METHODS This retrospective cross-sectional study describes the distribution of author gender as determined from the first name across variables such as authorship position (first, middle, and last), country region, and country income level. The 608 articles with 5,302 authors included in this analysis were published in the Journal of Clinical Oncology Global Oncology, from its inception in October 2015 through March 2020. Primary outcome measure was author gender on the basis of first name probabilities assessed by genderize.io. World Bank classification was used to categorize the country region and income level. Odds ratios were used to describe associations between female last authorship and representation in other authorship positions. RESULTS Although female authors were in the minority across all authorship positions, they were more underrepresented in the last author position with 190 (32.1%) female, compared with 252 (41.4%) female first authors and 1,564 (38.1%) female middle authors. Female authors were most under-represented among authors from low-income countries, where they made up 21.6% of first authors and 9.1% of last authors. Of all the regions, sub-Saharan Africa and South Asia had the lowest percentage of female authors. Compared with articles with male last authors, those with female last authors had odds ratios (95% CI) of 2.2 (1.6 to 3.2) of having female first authors and 1.4 (0.9 to 2.1) of having 50% or more female middle authors. CONCLUSION There are wide regional variations in author gender distribution in global oncology. Female authors remain markedly under-represented, especially in lower-income countries, sub-Saharan Africa, and South Asia. Future interventions should be tailored to mitigate these disparities.