ATLAS studies of diffraction, soft particle production and double parton scattering

Soft and semi-hard QCD studies made with ATLAS are presented. These include measurement of the inelastic and diffractive cross sections, mean forward energy flow, forward-backward and azimuthal correlations, azimuthal ordering of hadron production, event shapes, and identified strange particle production. Distributions sensitive to the underlying event are measured in a variety of hard processes. In addition, an explicit study of double-parton scattering using W+dijet events is presented, along with a measure of the effective cross section. Many of these measurements are used to develop and tune models for soft particle production. An overview of these results is given.