This study was conducted to examine students' perceptions of collaboration, socialization and task complexity in an online collaborative learning environment. Implementation of the collaborative learning was performed via Google Docs. The study group consists of 43 fourth grade university students who take "Research Methods" course. The students were divided into 11 groups. The students were expected to prepare a research proposal in line with the problem statement which was determined by themselves as part of their project. The implementation process of the study was conducted for 3 weeks. In the research, three scales were applied to the students to measure their perceptions of collaboration, socialization and task complexity; in addition to these, the log data were saved. Anova, Manova, Hierarchical Clustering Analysis and Pearson's Correlation Analysis were used for data analysis. As a result of the analysis, when the descriptive statistics were examined, it was obtained that the students' average scores of perception of collaboration and socialization were medium, the average score of perceived task and environment complexity was slightly above the medium, and the average score of perceived environment-task interaction complexity was high. Hierarchical Clustering Analysis was applied by using the variables of "contribution to the project", "rate of studying synchronously" and "group performance", with the aim of clustering the students with respect to their performances in the environment. 3 clusters, low, medium and high, were obtained as the result of the clustering analysis. When the students' perceptions of collaboration, socialization, task, environment and environment-task interaction complexity were examined based on their performance in the environment, it was observed that there is a significant difference between the groups in terms of environment-task interaction complexity. Also, when the correlations between the students' contribution to the project, the rate of studying synchronously with the group members and the groups' project performance scores were examined, it was observed that there is a positive, significant and high correlation between the personal contribution and the rate of studying synchronously. When the correlation between students' perceptions of collaboration, socialization, task complexity, environment complexity and environment-task interaction complexity were analyzed, a positive, significant and high correlation between the perceptions of socialization and collaboration; a positive, significant and medium correlations between the perceptions of socialization and task complexity and between the perceptions of environment complexity and environment-task interaction complexity were obtained. The task, environment and environment-task interaction complexities are observed to be positively, significantly and highly correlated.