Lack's Dock is a slipway onto the River Thames at Vauxhall, situated adjacent to MI6's SIS Building in London. The site was historically used as the river-access point for the amphibious London Duck Tours vehicles, which entered the Thames here.

Navigation risk assessments associated with the nearby Tideway construction project noted the importance of managing river users around the slipway to prevent drifting onto submerged structures.

The slipway was closed during works related to Thames Water's Tideway Project and subsequently reopened, with the area renamed Effra Quay following completion of that scheme in 2017.