Aggregating multiple 802.11 Access Point (AP) backhauls using a single-radio WLAN card has been considered as a way of bypassing the backhaul capacity limit. However, current AP aggregation solutions greedily maximize the individual station throughput without taking fairness into account. This can lead to grossly unfair throughput distributions, which can discourage user participation and severely limit commercial deployability. Motivated by this problem, we present THEMIS, a singleradio station that performs multi-AP backhaul aggregation in a fair and distributed way, without requiring any change in the network. We implement THEMIS on commodity hardware, evaluate it extensively through controlled experimental tests, and validate it in a deployment spanning 3 floors of a multistory building. THEMIS is being used in a commercial trial by a major broadband provider to its customers. Categories and Subject Descriptors C.2.5 [Computer Communication Networks]: Local and Wide-Area Networks-...