Military operations are constantly evolving, requiring leaders to adapt to new challenges. The Internet of Things (IoT) has emerged as a solution to these challenges, integrating sensing, actuator, and control systems with existing infrastructure. This approach has significantly impacted various industries, including military and defence applications. To address the major challenges to IoT security from the perspective of the defence industry, the editors of The Internet of Things in the Defence Industry: Challenges and Solutions for Military Security have collected chapters to focus on contemporary topics related to IoT security. They discuss the consequences of IoT security from the perspective of the defence sector before evaluating, addressing, and offering recommendations. Unique to this collection is the possible decision-making solutions, which provides effective recommendation-related solutions. Further, this work tackles a topic that has never been addressed, especially from the standpoint of the defence industry: safeguarding IoT applications against manipulation in a defence organisation in numerous ways in order to maintain security. The Internet of Things in the Defence Industry marks a turning point in the defence industry by providing new perspectives for researchers and security suggestions for engineers. It also aids those learning about IoT security for the first time by presenting it from the perspective of the defence sector.