The gene quiver/sleepless (qvr/sss) plays a critical role in the regulation of sleep in Drosophila melanogaster . Its protein product SLEEPLESS (SSS) is a small, glycosylphosphatidylinositol (GPI)-anchored protein enriched in Drosophila brains. Predicted to belong with the Ly-6/neurotoxin superfamily, SSS is hypothesized to interact with other proteins at the plasma membrane. One potential candidate for a SSS interaction is the canonical voltage-gated K⁺ channel, Shaker, as sss/qvr mutants exhibit changes in three aspects of in situ Shaker currents: decreased magnitude, slower time-to-peak, and the emergence of a fast inactivating, slow-recovering component, called I _AS. It is the aim of this body of work to increase our understanding of the SSS-Sh interaction. Using the Drosophila larval neuromuscular junction as a model system, I demonstrate that SSS acts cell-autonomously to modulate in situ Shaker currents. Furthermore, SSS accelerates the kinetics of heterologously expressed wildtype Shaker channels in a manner consistent with the in situ data. I also show that SSS specifically increases the rate of Shaker current activation with little or no effect on the rates of deactivation or fast, N-type inactivation. An established model of Shaker gating kinetics predicts that this SSS-induced acceleration in activation is sufficient to explain the slower time-to-peak of in situ Shaker currents in qvr/sss mutants. SSS coexpression also decreases the rate of in vitro Shaker C-type inactivation, suggesting that the unasking of I_AS in qvr/sss mutants is caused by an increase in the rate of entry into a C-type inactivated state. Furthermore, the SSS-dependent effects on activation and C-type inactivation may comprise nearly 40% of the total decrease in Shaker current magnitude in the qvr/sss null mutant. Finally, I also provide biochemical and electrophysiological evidence supporting a role for lipid rafts in the SSS-induced kinetic effects, which could lend insight into how SSS modulates Shaker channels in vivo.