mm-Wave frequency bands are steadily becoming a key enabler for the next generation communications systems. From 6G to super-secure short-range communications, the increasing frequencies of operation are putting ever more stringent performance requirements on the semiconductor technologies, that in turn push the requirements of device characterization techniques. Load-pull has long been a critical device characterization method providing information about the best device performance under the small- and large-signal operating conditions. With the increasing device operating frequencies, the load-pull setups are increasing in complexity. During this talk we will review the fundamentals of passive, active and hybrid-active load-pull techniques used to characterize devices at mm-wave frequencies, and present the benefits and drawbacks of each implementation. We will then present practical implementations of each setup and discuss key performance considerations. Finally, the requirements for power and frequency scalability of mm-wave passive impedance tuners and load-pull setups, and the associated challenges will be discussed.