'Fusion meets chaotic dynamics'—this was the headline for the Fifth International Workshop on Stochasticity in Fusion Plasmas (SFP) held in Jülich, Germany from 11–14 April 2011. This headline reflects a landmark as the generic topic of chaotic dynamical systems has emerged a prominent application by controlling the plasma stability and transport. The workshop facilitated once more gathering of expertise from basic research in the field of non-linear dynamic systems and experts on plasma stability and transport from magnetically confined high temperature plasmas.Resonant magnetic perturbations are used in most large-scale fusion experiments for control of the cyclic high heat flux pulses caused by edge-localized modes in high performance plasmas. This is one of the most prominent applications of non-linear perturbation schemes in modern plasma physics. It was experimentally shown that the edge transport in toroidal magnetic confinement systems as tokamaks and stellarators can be improved towards elimination of transient events, reduction of steady state heat flux densities and reduction of impurity inflow with improvement of the particle confinement. These results sketch the versatile application space of small-scale perturbations for optimization of the rigid magnetic cages used in magnetic confinement of fusion plasmas.At the same time, these experimental observations represent a challenge to theory. The understanding of the experimental observations for extrapolation to future devices is a root requirement in this field of research. Two aspects were dominant in the workshop. First, the question of how the high temperature plasma as highly conductive media with potentially high rotation and plasma drift speeds reacts to a stationary external perturbation was central in all discussions on structural formation, related transport effects and interaction to plasma stability. Second, the topic was highlighted in how far the perturbed system and the final plasma stage is optimized in view of plasma–wall interaction.The papers published in this special issue represent an overview of key aspects discussed at the workshop. This selection is a vital mixture taken out of the following four topical sessions: (1) Formation of stochastic magnetic layers and plasma response to external, non-axisymmetric magnetic perturbations; (2) Energy and particle transport in stochastic magnetic fields; (3) Exhaust in helical and island divertors; (4) Application of resonant magnetic perturbations for ELM control and implications for ITER. Each topical session was concluded with an appended discussion session. An overview of the key points identified in these discussion sessions is given in the workshop summary.The next workshop is planned for early 2013. For details please see www.fz-juelich.de/sfp/. We hope this special issue of Nuclear Fusion will give a stimulating overview of the newest results in this field and highlights key aspects for application in next step fusion devices.