Electrospinning is a valuable production method for nanoscale polymeric fibers. A major limitation of the technology is the requirement for high molecular weight polymers as a major part of the matrix. Many applications would benefit from flexibility in the materials for electrospinning, including pharmaceuticals, wearable devices and diagnostics, and structured fibers with particles included that are larger than the fiber size. To realize these more advanced functional composites, a strong understanding of how particle inclusion affects the electrospinning process and mat properties is essential. In this work, we examine materials systems containing polymers and microparticles, focusing on how inclusion of particles affects the electrospinnability and morphology of the fiber. The primary factors that influence electrospinnability and morphology are the particle density, particle aggregation, and size ratio of the fibers to the particles. These results provide a platform for product design for new electrospun materials with high loadings of functional particles.