Extensive research has established organic-inorganic hybrid perovskites as a promising material for optoelectronic device applications. Especially for lasers, many optically driven amplified spontaneous emission and lasing reports have been demonstrated across the near infrared to the green in various configurations (distributed feedback (DFB), distributed Bragg reflectors, photonic crystals, etc) and pumping regimes (from pulsed to continuous-wave excitation) at low threshold, allowed by the tunable bandgap energy by controlling halide stoichiometry or material dimensionality. However, most reports lack red-emitting lasing action at room temperature due to undesirable halide phase separation that produces iodide-rich and bromide-rich domains in mixed-halide perovskites under intense illumination, resulting in a ‘red gap’ problem where bandgap becomes pinned to the lower iodide-rich phase. Here we demonstrate a red-emitting 2nd-order DFB laser operating at room temperature from solution-processed organic-inorganic hybrid perovskite thin films for the first time. Ultra-flat mixed-halide perovskite layers were prepared on a quartz grating to achieve single-mode surface-emitting laser emission for at least a few tens of minutes (~ 10^6 pulses) with a threshold of 85 µJ/cm^6 and full-width-half-maximum of less than 1.5 nm under picosecond-pulsed optical excitation. We effectively suppress phase separation by properly choosing self-assembled long-chain organic ammonium halide additives to enable stable lasing action over a wide range of wavelengths near the red. Our results provide a significant step towards full-color visible laser device applications from cost-effective halide perovskite material systems.