Query object localization, segmentation, and retrieval are disclosed. A query image may be received that includes a query object. Based on respective spatially constrained similarity measures between the query image and a plurality of images from an image database, at least some of the plurality of images may be identified and/or retrieved and a location of the query object in the query image may be estimated. The query object may then be automatically segmented from the query image based on the estimated query object location. In some embodiments, the retrieval, localization and/or segmentation may be iterated.