The sixth in the series of biennial Portorož workshops will take place from September 21st to 24th, 2021. The aim of the workshop is to discuss complementary aspects of precision elementary particle phenomenology both within the standard model and beyond: those relevant for the third and high luminosity runs of the Large Hadron Collider and possible future high energy colliders; in high intensity experiments measuring quark/lepton number, flavour and CP violation; in astroparticle experiments probing the matter content of the universe. Planned topics to be covered include Higgs boson and electroweak physics, top quark physics, flavour phenomena and CP violation, neutrino physics, dark matter as well as other particle dynamics in the early universe. The program will consist of plenary talks covering recent theoretical advances in the field as well as a small number of experimental reviews.