β-Aminobutyric acid is a non-proteinogenic amino acid that is known to protect plants against various pathogens. Its structure is midway between α-aminobutyric acid and γ-aminobutyric acid. The structural differences in the position of the amino group in the conformational stabilization of β-aminobutyric acid have been studied by laser ablation Fourier transform microwave spectroscopy. Five conformers have been detected, and their rotational and quadrupole coupling constants of the 14N nucleus determined. Three of the conformers, including the most stable structure, are stabilized by a non-bifurcated N-HO[double bond, length as m-dash]C intramolecular hydrogen bond. The other two conformers possess a NH-O intramolecular interaction. In this work we highlight that β-aminobutyric acid shows the conformational peculiarities of α-aminobutyric acid and γ-aminobutyric acid completing the rotational spectroscopic study of the x-aminobutyric acid series.