In this paper, we study an analog of Titchmarsh’s theorem for the Hartley–Bessel transform on the real line. Using the Hartley–Bessel operator \(\Lambda _\alpha \) , the associated generalized translation, and suitable higher-order differences, we obtain integrability and decay estimates for the Hartley–Bessel transform in weighted \(L^p\) spaces. More precisely, we prove conditions ensuring that \(\mathcal {H}_\alpha (f)\) belongs to \(L^\beta (\mathbb {R},d\mu _\alpha )\) , where \(1<p\le 2\) . We also introduce a Hartley–Lipschitz class defined by means of the operator \(\Lambda _\alpha \) and establish a corresponding estimate for the tail integral of the transform. Finally, in the Hilbert space case \(p=2\) , we prove an equivalence between this Hartley–Lipschitz condition and a decay estimate for the Hartley–Bessel transform.