This study assessed whether the Recovery-Stress Questionnaire for Athletes (RESTQ-Sport) could be used to monitor changes in perceived stress and recovery during intensified training of rugby league players. 20 semiprofessional rugby league players were divided into two equal groups randomly assigned to complete 6 wk. of Normal Training or Intensified Training, each followed with a 7-day taper. Multistage Fitness Test performance and RESTQ-Sport measures were taken at the beginning, at 2-wk. intervals, and at the end of the training period. Endurance significantly decreased with Intensified Training and returned to baseline levels following the taper, while remaining unchanged in the Normal Training group. The RESTQ-Sport scores with training were positively related to stress subscale scores (Fatigue, Disturbed Breaks, and General Stress) and recovery subscale measures (Success, Physical Recovery, Being in Shape, Self-efficacy, Social Relaxation, General Well-being, and Sleep Quality) decreasing in the Intensified Training group and then normalising following the taper (Stress subscales: Fatigue and General Stress, and Recovery sub-scales: Physical Recovery and General Well-being). The RESTQ-Sport is a practical psychometric tool for monitoring responses to training in team-sport athletes.