Techniques described herein for coding video data include techniques for coding pictures partitioned into tiles, in which each of the plurality of tiles in a picture is assigned to one of a plurality of tile groups. One example method for coding video data comprising a picture that is partitioned into a plurality tiles comprises coding video data in a bitstream, and coding, in the bitstream, information that indicates one of a plurality of tile groups to which each of the plurality of tiles is assigned. The techniques for grouping tiles described herein may facilitate improved parallel processing for both encoding and decoding of video bitstreams, improved error resilience, and more flexible region of interest (ROI) coding.