The main goal of this research was to construct a quality measuring instrument for assessing group properties (cohesion, perceived collective efficacy and coaching behavior) in volleyball. The research was conducted on a sample of 273 youth and junior male and female volleyball players. The pilot testing included 147 participants of both sexes, and based on their responses, items of the newly constructed questionnaire for assessing group properties (cohesion – 13 items, perceived collective efficacy – 14 items and perceived coaching behavior – 14 items) were selected. With the purpose of validating the newly constructed questionnaire of team properties, the following existing questionnaires for assessing group properties were also used: - GEQ (Group Environment Questionnaire), and the team orientation scale from the PSIS-Y questionnaire (Psychology skills inventory for sports – youth version) for assessing cohesiveness - LSS (Leadership Scale for Sport), and CBS-S – (Coaching Behavior Scale for Sport) for assessing coaching behavior Collective efficacy was assessed based on team’s success (team placement in 2011 Croatian championship), and the efficiency of each individual male/female player (assessment based on coaches’ evaluation or players’ performance in the national team). Nine factors – dimensions which explain 58.44% of the total variance of the system were isolated by matrix factorization of the item set of the newly constructed questionnaire, and by (oblimin) rotation. It has been established that the measured features were not homogenous and were difficult to interpret, so data analysis was conducted separately for each area – facet of group properties. By analyzing the metric characteristics of scales in the newly constructed questionnaire, it has been established that the reliability of the scales ranges from an unsatisfactory 0.68 and 0.69 in scales of social cohesion and coaching style, to a very good 0.85 in the scale of satisfaction with the coach and 0.87 in task cohesion. For the purposes of data analysis on a team level, all of the obtained values are acceptable. Even though the K-S test results indicate that the result distribution of 4 out of 6 measures of group properties deviates from normal distribution, it has been concluded, based on distribution shape and symmetry indicators, that parametric procedures can be conducted on the obtained scales. By validating the existing measures of GEQ and PSIS-Y scale for assessing group properties, it has been established that the reliability of all scales assessing cohesiveness (except social integration of the group) was less than satisfactory (between 0.60 and 0.70). By validating the existing questionnaires of perceived coaching behaviour (LSS and CBS-S), it has been established that the reliability was good in all 7 scales of CBS-S, as well as in 3 out of 5 scales of the LLS questionnaire. The reliability was not satisfactory only in scales of autocratic behaviour and positive feedback. The distribution shape and symmetry indicators indicate good sensitivity of all scales, and having the item selection performed in particular scales, all scales have good homogeneity. By correlation analysis, statistically significant, moderate to moderately high correlations were found between the measures of the newly constructed questionnaire for assessing cohesion, perceived collective competence and coaching behavior, which indicates they might have a common source. Even though two latent dimensions have been determined by factorization (group properties and coach’s communication style), eigenvalue of the second component, which was only slightly above the threshold in the initial structure, implies that if the sample was increased, only one latent dimension - the component of group properties of volleyball teams would be found. Positive (moderate to high) correlations were also found between the scales of group properties of the newly constructed questionnaire and the corresponding scales of the existing questionnaires. Therefore, the newly constructed questionnaire can be recommended as the compact orientation measure of group properties. By testing the differences between the sexes, it has been established that there were no significant differences in the level of group properties measured by the newly constructed questionnaire. By applying validated GEQ and PSIS-Y questionnaires, significant differences were found in cohesion, in 3 out of the 5 variables. Female players expressed significantly higher individuals’ personal attraction to group - task (volleyball) as well as – social. Also, female players expressed significantly higher group integration - task (volleyball). By applying validated LSS and CBS-S questionnaires, significant differences were found in the level of measured properties of coaching behavior in 5 out of the 12 variables. Female players, as opposed to male players, evaluated their coaches’ behavior as more democratic and less autocratic, with coaches also paying more attention to practicing technical elements of volleyball and strength and conditioning training. By testing the differences between the age groups, it has been established that female players of the younger age group expressed higher task cohesion and gave a more positive evaluation of satisfaction and coach’s communication style than older players. Male players of the younger age group expressed higher team confidence than older players. Moreover, older female players were significantly more team oriented than younger female players, and younger male players expressed significantly higher social cohesion than older male players. Female players of the younger age group, in comparison to older players, evaluated their coaches’ behavior as more autocratic. By testing the differences between the two age groups of male volleyball players, there were no significant differences found in the level of validated measures of coaching behavior. By variance analysis performed in male and female subsamples of volleyball players, there were no significant differences found in the level of constructed measures of group properties among players in different positions. By performing a univariate analysis of variance, it has been established that female players with a lower index of individual player efficiency had a significantly higher level of perceived task cohesion and collective competence – readiness than players with the highest index of individual player efficiency. Moreover, the highest-rated female players assessed their coach’s communication style as least acceptable. The same conclusions can also be made about female players based on the analysis of results obtained by discriminant analysis. Among male players of different player efficiency, there were no significant differences found by variance analysis and discriminant analysis in the expressed level of any of the 6 constructed measures of group properties. Similar results were obtained by variance analysis and discriminant analyses of female players in relation to the index of team efficiency, establishing that groups of players with the lowest index of team efficiency are characterized by a high level of task cohesion and satisfaction with the coach and his communication style. Among groups of male players, variance analysis and discriminant analysis have shown that players with higher index of team efficiency, in comparison to players with lower index of team efficiency, gave higher evaluations in both variables of collective competence – readiness and confidence, as well as in task cohesion.