With the demanding requirement of nanotechnology in the semiconducting industry, the challenge will become unprecedented as the fabrication approaches the scaling limit in the next few years. The rise of 2D materials seems to be a probable solution for developing the next-generation semiconducting devices. As 2D lateral junctions bring a revolutionary breakthrough in the past few years, nanoscale sized devices are no longer limited to the vertical direction. Doping and structural design strategies that are totally different from conventional Si based devices can bring about more ideal and ultra-efficient electronic and optoelectronic devices. This perspective summarizes and compares different methods of 2D lateral junction designs (including electrostatic tunable p-n homojunction and direct growth of in-plane p-n heterojunction) and various material combinations (including metallic-insulating, semiconducting p-n, and ohmic junctions). In addition, examples of design strategies and what can be achieved by adopting these 2D lateral junctions have been provided to show the promising potential for the future development. It can be expected that over the next few years, 2D materials will dominate the semiconducting industry and holds the promise for keeping the Moore’s law alive.