This session is intended as a discussion forum to review and improve our current understanding of particle acceleration mechanisms in solar system plasmas from both experimental and theoretical point of view. In particular, this session should contribute to highlight the current and future synergies between in situ and remote observations, simulations, and theories. Synergism is crucial to establish how fundamental acceleration mechanisms operate in different solar system plasma environments (e.g. solar corona/wind, planetary magnetospheres). Such collaborative approach is strongly motivated by major observational advances, obtained with new generation of spacecraft like Cluster, Themis, Rhessi, Hinode, Stereo, SDO, etc, and future missions such as Solar Orbiter and Solar Probe Plus that will allow the first simultaneous in situ and remote observations in the solar corona/wind. We solicit contributions on the topic of particle acceleration mechanisms such as those operating in solar flares and planetary substorms during reconnection, in solar wind stream interfaces such as co-rotating interaction regions, at interplanetary and planetary shocks/foreshock regions and in radiation belts and auroral regions.