Purpose <p>The purpose of this study was to investigate the effects of caffeinated chewing gum on the cognitive tasks, strength and military performance of tier 1 special forces soldiers in Taiwan.</p> Methods <p>Sixteen male serving special forces soldiers (age: 34 ± 7 years; height: 172 ± 4&#xa0;cm; BMI: 25.4 ± 2.7&#xa0;kg/m²) completed the caffeinated chewing gum (CAF) trial and the placebo (PL) trial using a randomised crossover experimental design. After chewing the caffeinated chewing gum containing 3&#xa0;mg·kg^− 1 of caffeine (CAF trial) or placebo gum (PL trial), participants completed the cognitive tasks, grip strength, weighted vertical jump and the special forces military performance tests which included rapid-fire test and close-quarters battle (CQB) tests. Before, during, and after the experiment, the heart rate variability and salivary α-amylase were collected.</p> Results <p>Grip strength (increase 4.4 ± 7.1&#xa0;kg; <i>P</i> = 0.037), weighted vertical jump height (increase 1.3 ± 2.1&#xa0;cm; <i>P</i> = 0.032), cognitive tasks (simple response times, stroop task and visual search reaction time in 20 items) (<i>P</i> &lt; 0.05), shooting scored in rapid-fire test (increase 1.0 ± 2.1 points; <i>P</i> = 0.030), the CQB tests (increase 1.1 ± 1.8 points; <i>P</i> = 0.044) and the completion times of CQB tests (increase 9.8 ± 7.2&#xa0;s; <i>P</i> = 0.015) of the CAF trial were significantly better than those of the PL trial. The values of LF, LF/HF, salivary caffeine and α-Amylase concentration in the CAF trial were significantly higher compared to the PL trial (<i>P</i> &lt; 0.05).</p> Conclusions <p>Caffeinated chewing gum may improve military performance and cognitive performance by increasing sympathetic nervous system activity, as indicated by heart rate variability and salivary α-amylase concentration in CAF trials.</p> Trial Registration <p>The study was registered at ClinicalTrials.gov ID NCT06638372.</p>