General odorant-binding proteins (GOBPs) are believed to transport a wide range of volatile hydrophobic molecules across the aqueous sensillum lymph toward olfactory receptors in insects. GOBPs are involved in the first step of odorant recognition, which has a great impact in agriculture and in insect-mediated human disease control. We report here the first structural study of a GOBP, the honeybee ASP2, in complex with a small hydrophilic ligand. The overall fold of the NMR structure of ASP2 consists of the packing of six α-helices creating an internal cavity and closely resembles that of the related pheromone-binding proteins (PBPs). The predominantly hydrophobic internal cavity of ASP2 provides additional possible interactions (π-stacking, electrostatic contact) for ligand binding. We also show that the internal cavity of ASP2 has the ability to bind ligands of different structures and properties, including a hydrophobic component of the floral scent [2-isobutyl-3-methoxypyrazine (IBMP)] and a small hydrophilic ligand. We further demonstrate that IBMP binds ASP2 with two stable alternative conformations inside the ASP2 binding pocket. The ¹⁵N NMR relaxation study suggests that significant backbone mobility occurs at the ligand entry site at the millisecond rate, which likely plays a role in the recognition and the uptake−release mechanism of ligands by ASP2. We propose that the broad ligand specificity of GOBPs compared with PBPs is conferred by the cumulative effects of weak nonspecific protein−ligand interactions and of enhanced protein internal dynamics at the ligand entry site.