An electrical connector assembly includes a first electrical connector and a second electrical connector. Each electrical connector can include a plurality of electrical ground shields that at least partially surround respective differential signal pairs. The electrical connectors can be constructed so as to reduce cross-talk between adjacent signal pairs. For example, the first electrical connector can include a connector housing defining an end that is configured to be mounted to a substrate. The ground shields can define a body that extends through the connector housing, such that the ground shields extend through the end so as to be disposed between the end and the substrate when the connector is mounted to the substrate.