This chapter focuses on the behavior of plasmonic structures in the close vicinity of gain media. It provides an outlook on the future possibilities of gain-assisted plasmonic devices. Surface plasmons (SPs) have attracted great attention due to their potential applications in various fields of science and technology. For localized SP resonance, the compensation of loss by the gain material is shown as the enhanced polarizability and narrowing of resonance peak line width. For propagating surface plasmon polaritons (SPPs), people first studied the enhanced propagation length upon the implementation of gain media with various waveguide configurations. The chapter discusses the lasing and amplification of a lossy propagating SPP mode. Great successes have been achieved in the areas of amplification of long-range surface plasmon polaritons using fluorescent materials, stimulated emission from metal-dielectric core-shell nanoparticles, and stimulated emission from hybrid SP modes at the metal insulator semiconductor interfaces.