In the current landscape of antiretroviral options, there remains an urgent need for novel non-nucleoside reverse transcriptase inhibitors (NNRTIs) with improved resistance profiles and safety properties. Herein, a series of novel tetrahydropyrido[4,3-d]pyrimidine derivatives were discovered utilizing the "escape from flatland" strategy. The most potent inhibitor 10c was endowed with broad-spectrum antiviral activity and improved resistance profiles against NNRTI-resistant variants compared to efavirenz and etravirine. Molecular simulations were investigated to furnish insights into the biological results. Drug-likeness assessment showed that 10c exhibited desirable physicochemical properties and in vitro metabolic stability. Notably, lower cytochrome P450 inhibition and human ether-à-go-go-related gene blockade liability were observed for 10c than those for etravirine and rilpivirine. Besides, 10c was characterized by excellent in vivo safety properties without acute/subacute toxicity and organ pathological damage. Overall, our multiparameter optimization campaign led to the identification of 10c with excellent antiviral activities and favorable drug-like profiles that could serve as an ideal drug candidate for further development.