Metastability is a dynamical phenomenon common in a wide variety of natural systems, such as large bio-molecules, chemical reactions, and global climate systems for example. Many mathematical models have been devised to better understand and analyze this phenomenon. Some of them are motivated by specific problems in applications; others serve as more general descriptions of complex metastable systems. Randomness is a natural feature of such models. The theory and simulation of metastable systems over the last decades have seen a great development, thanks to the combinations of techniques coming from various research areas of mathematics, ranging from probability, analysis, statistical physics, numerics, high performance computing and dynamical systems. The objective of this workshop is to gather applied mathematicians from these different communities to exchange ideas about recent advances on the mathematical analysis and the simulation of stochastic metastable dynamics, with a particular emphasis on the newest developments and on future directions. Here are several problems that will be addressed: Analysis of the mean exit time from a metastable region (Eyring-Kramers law, exact formulas by potential theoretic approaches); Characterization of typical trajectories, typical exit locations from a metastable region and critical configurations (nucleation, large deviation, rare events sampling, quasi-stationary distributions); Characteristic time-scales of longtime dynamics (Markovian process and generators, coarse-grained dynamics, martingale method). The workshop will bring together both experienced researchers and promising young scientists from different scientific backgrounds, interested in the interplay between theoretical and applied research. It will promote the participation of male and female researchers with a good gender balance among speakers. The conference will place an emphasis on the connections between the areas and on directions for future research. We expect a high-level and high-impact event which will inspire new collaborations and will open new research directions.