  The 2nd Anti-UAV Workshop \& Challenge aims to encourage research in
developing novel and accurate methods for multi-scale object tracking. The
Anti-UAV dataset used for the Anti-UAV Challenge has been publicly released.
There are two subsets in the dataset, $i.e.$, the test-dev subset and
test-challenge subset. Both subsets consist of 140 thermal infrared video
sequences, spanning multiple occurrences of multi-scale UAVs. Around 24
participating teams from the globe competed in the 2nd Anti-UAV Challenge. In
this paper, we provide a brief summary of the 2nd Anti-UAV Workshop \&
Challenge including brief introductions to the top three methods.The submission
leaderboard will be reopened for researchers that are interested in the
Anti-UAV challenge. The benchmark dataset and other information can be found
at: https://anti-uav.github.io/.
