A state-space modeling framework for microgrid small-signal stability analysis is developed in this paper. The proposed framework is intrinsically modular, in the sense that each elementary microgrid component is individually modeled and then aggregated into a single model for the entire microgrid. The microgrid model includes the representation of fast dynamic phenomena that arise with the widespread use of electronically interfaced microsources typical of microgrid applications. Therefore, the dynamics of (i) microsources and associated controllers and electrical filters; (ii) loads, and (iii) the electrical network, are all taken into account. The proposed modeling framework is applied to a particular microgrid, and the resulting small-signal model is used to perform controller design, microgrid small-signal stability analysis and to investigate dynamic interactions between microsource controllers in both grid-connected and islanded operating modes. The proposed modeling framework is validated through the comparison of the small-signal stability analysis results with nonlinear time-domain simulations performed with the PSCAD software package.