This chapter presents an overview of recent developments in the integration of 2D materials, specifically graphene and MoS2, with nitride semiconductors for electronics and optoelectronics. The state-of-the-art approaches for the fabrication of heterojunctions between these two classes of materials are discussed, considering advantages and limitations. Although the chemical vapor deposition (CVD) growth of graphene on AlN at high temperatures (>1250 °C) have been recently reported, the transfer of Gr grown on catalytic metals still remains the main approach to integrate graphene with GaN materials. On the other hand, many progresses have been reported in the lattice-matched CVD growth of MoS2 monolayer on GaN, as well as in the use of MoS2 as templates for strain-free GaN deposition. Examples of novel electronic devices based on 2D material/nitride heterostructures are presented, such as the hot electron transistor (HET) with a Gr base and a Al(Ga)N/GaN emitter for THz electronics and the band-to-band tunneling diode based on p+-MoS2/n+-GaN heterojunctions for digital electronics with ultralow-power dissipation. Furthermore, optoelectronic devices based on the integration of 2D materials with GaN are discussed, such as GaN blue LEDs with graphene-transparent conductive electrodes and deep UV photodetectors based on n-MoS2/p-GaN heterojunction. Finally, some results on the use of Gr heat spreaders for thermal management in high-power AlGaN/GaN high electron mobility transistors (HEMTs) are presented.