This study identified factors and variables of informal leadership in small groups with different gender composition (Men, women and mixed groups) and goal orientation (competition and cooperation). Behavioral dominance patterns (Information Sheet, pencil, decision sheet) and number of verbal interventions were compared to the main informal leadership factors identified in the groups. There were 24 participants (12 men and 12 women). Among the main variables and factors identified, there were some that had a higher possibility to appear than other. There was no significant difference of the factors and variables between women and men. Communication variables were more likely to be present in groups with the goal of cooperation as for the goal of competition. Guidance variables were more likely to be present in women groups than in men groups and mixed groups. There was a significant correlation between the factor’s Communication, Character and Guidance with the number of interventions and behavioral dominance patterns.