Monolithic total internal reflection resonators confine light through traveling-waves that can feature high quality factors and small mode volumes. Such resonators have emerged as rigid and compact platforms to explore high-efficiency laser-matter interactions and their related applications in photonics technology. In this review, we focus on monolithic ring resonators based on total internal reflection, with a particular emphasis on nonplanar ring oscillators and whispering-gallery mode lasers. We also discuss resonantly enhanced nonlinear photonic systems based on these resonators, using both non-centrosymmetric and centrosymmetric optical materials.