The $Q$-Fourier-Dunkl transform satisfies some uncertainty principles in a similar way to the Euclidean Fourier transform. By using the heat kernel associated to the Q-Fourier-Dunkl operator, we establish an analogue of Beurling's theorem for the $Q$-Fourier-Dunkl transform $\mathcal{F}_{Q}$ on $\mathbb{R}$.