In this paper we examine the gender split in 76,981,561 bicycle share trips made from 2014-2018 for three of the largest public bicycle share programs in the U.S.: Bluebikes (Boston), Citi Bike (New York), and Divvy Bikes (Chicago). Overall, women made only one-quarter of all bicycle share trips from 2014-2018. The proportion of trips made by women increased over time for Citi Bike from 22.6% in 2014 to 25.5% in 2018, but hovered steady around 25% for Bluebikes and Divvy Bikes. Across programs, the gender gap was wider for older bicycle share users.In this article we examine the gender split in bicycle share trips made between 2014 and 2018 for three of the largest public bicycle share programs in the United States: Bluebikes (Boston), Citi Bike (New York), and Divvy Bikes (Chicago). We hypothesized that men would make more bicycle share trips than women, but that the gap would decrease over time.