This disclosure describes techniques for scanning coefficients of video blocks. In particular, the techniques of this disclosure adapt a scan order used to scan a two-dimensional block of coefficients into a one-dimensional coefficient vector based on statistics associated with one or more previously coded blocks. For example, statistics that indicate the likelihood that a given coefficient value in each position of a two-dimensional block is zero or non-zero may be collected for one or more previously coded blocks. At some point, an adjustment to the scan order can be made in order to better ensure that non-zero coefficients are grouped together near the front of the one-dimensional coefficient vector, which can improve the effectiveness of entropy coding. The collection of statistics and adjustment of scan order may be made separately for each possible prediction mode.