This study investigates the recognition of halide anions by N,N’-bis(4-nitrophenyl)urea using computational methods in both gas-phase and solution. It examines interaction, stabilization, and deformation energies, revealing a gas-phase selectivity trend of [L⋯F]−>[L⋯Cl]−>[L⋯Br]−> [L⋯I]−. NBO, QTAIM, and EDA-NOCV analyses highlight N-H∙∙∙X hydrogen bonds, with electrostatic forces contributing around 60% to the total interaction. Despite unfavorable solvation energy changes, the intrinsic affinity remains the main factor for selectivity, which aligns with experimental data. The strong correlation between theoretical and experimental formation constants supports the reliability of the computational findings.