Citrus cultivation is challenging due to the plethora of abiotic and biotic stresses faced by the crop. In recent years, production has been severely affected by diseases such as citrus canker and huanglongbing (HLB). Disease management is hampered as there is no field resistance to these diseases in any of the important commercially planted varieties. Traditionally, conventional breeding approaches have been applied for the improvement of the susceptible cultivars; however, this technique is laborious and time consuming. Genetic transformation of citrus allows for the rapid integration of novel genes into the plant’s genome to develop disease-resistant transgenic plants. Therefore, efforts have been made to utilize genetic engineering tools to develop genetically modified citrus that are resistant to citrus canker and HLB. This review summarizes the major achievements made in the development of citrus canker and HLB tolerance using transgenic technologies.