<p>Linearly polarized photodetectors (PDs), leveraging the inherent structural and material information encoded in light’s polarization state, hold transformative potential for applications ranging from remote sensing to biomedical imaging. Traditional systems that rely on external polarizing elements face challenges in miniaturization and efficiency, driving interest in materials with intrinsic anisotropy. Low-dimensional metal halide perovskites, distinguished by their tunable bandgaps, high carrier mobility, and quantum confinement effects, have emerged as a groundbreaking platform for next-generation polarized PDs. This review comprehensively summarizes the theory, materials, and device engineering of linearly polarized PDs based on low-dimensional perovskites. It aims to elucidate polarization mechanisms across dimensions by establishing a rigorous theoretical foundation for linearly polarized PDs of low-dimensional perovskites. Beyond theoretical insights, the review also highlights cutting-edge fabrication techniques for one-dimensional nanowires and two-dimensional heterostructures, along with performance benchmarks of state-of-the-art devices. By integrating experimental advancements with theoretical insights, this work not only advances the fundamental understanding of polarization mechanisms but also outlines actionable pathways for optimizing device performance, stability, and scalability, which may serve as a critical resource for researchers aiming to harness the full potential of low-dimensional perovskites in polarized optoelectronics.</p>