IoT^2: A benchmark for the things in the Internet of Things Attacks against IoT systems are increasing at an alarming pace. Many IoT systems are and will be built using lowcost micro-controllers (IoT-\uCs). Different security mechanisms have been proposed for IoT-\uCs with different trade-offs. To guarantee a realistic and practical evaluation, the constrained resources of IoT-\uCs require that defenses must be evaluated with respect to not only security, but to performance, memory, and energy as well. Evaluating security mechanisms for IoT-\uCs is limited by the lack of realistic benchmarks and evaluation frameworks. This burdens researchers with the task of developing not only the proposed defenses but applications on which to evaluate them. As a result, security evaluation for IoT-\uCs is limited and adhoc. A sound benchmarking suite is essential to enable robust and comparable evaluations of security techniques on IoT-\uCs. This paper introduces IoT^2, a benchmark suite and evaluation framework to address pressing challenges and limitations for evaluating IoT-\uCs security. The evaluation framework enables automatic evaluation of 14 metrics covering security, performance, memory usage, and energy consumption. The IoT^2 benchmarks provide a curated set of five real-world IoT applications that cover both IoT-\uCs with and without an OS. We demonstrate IoT^2 ability by evaluating three defense mechanisms. All benchmarks and the evaluation framework will be open sourced upon publication.