Researchers are increasingly aware of the role of spatial skills in preparing children for future mathematics achievement (National Mathematics Advisory Panel, 2008). In addition, sex differences have been consistently documented showing boys score higher than girls in assessments of spatial ability, particularly mental rotation (Linn & Peterson, 1985; Masters & Sanders, 1993). While sex differences are well established, few studies have focused on kindergarten students' spatial ability and sex differences. Those studies that do exist were conducted 10-to-20 years ago, and may no longer be relevant in light of children's changing play experiences. This study examined the relationships between gender, kindergarten students' home block play behavior and their test total scores on a Block Design test and Mental Rotation Task. The goal of the study was to develop a deeper understanding of the play experiences or activities that may help to improve young children's spatial abilities and mathematics experiences. While block play has been found to contribute to the development of spatial ability skills in young children (Shore, 1977; Hirsch, 1984), no studies have directly addressed the relationship between kindergarten students' spatial abilities and their home block play. The study examined the block play experience and spatial ability tests of 96 kindergarten students. Archival data from two spatial ability tests, as well as data collected from a parent questionnaire regarding home block play experiences were utilized for the purpose of this study. Utilizing chi-square and t-tests, the relationships between the block play experience variables were investigated and indicated significant differences exist in the block play experiences of kindergarten boys and girls. Next, an investigation using Spearman's correlation was conducted to investigate relationships among predictor variables and spatial ability test scores. Results indicated block and LEGO play were correlated with the Mental Rotation Task. Regression analysis was additionally performed and results suggested minimal impact on Mental Rotation Task and Block Design test scores. Finally, the relationships among home block play experience variables, gender and spatial ability test scores were analyzed using hierarchical multiple regression. Results indicated minimal impact on spatial ability test scores. Gender had an impact on spatial ability scores. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]