Two main theoretical constructs seek to describe the elaborated sense of time that may be a uniquely human attribute: diachronic thinking (the ability to think about the past and use that information to predict future events) and event ordering (the ability to sequence events in temporal order). Researchers utilize various tasks to measure the emergence and refinement of diachronic thinking and event ordering in children and to document significant development in these skills during middle childhood. The current study investigated the relationship between performance on tasks of diachronic thinking and event ordering in 90 children (5;0-10;10) to determine whether these tasks tap overlapping cognitive processes. Specifically, we examined the extent to which the various measures were inter-correlated and related to measures of language and intelligence. A principal-components analysis yielded two factors. Factor 1 was positively associated with all measures, including age, language, and intelligence. Factor 2 (uncorrelated with age, language, and intelligence) distinguished the synthesis task from spatial and labeling tasks. Overall, results suggest that diachronic thinking and event ordering are not unified constructs. Rather, the multiple measures designed to assess these constructs tap into somewhat different ways of keeping track of time, and are distinguished by the extent to which they rely on knowledge of conventional time patterns and require flexibility in manipulating and synthesizing temporal sequences. Implications for how researchers conceptualize and assess time concepts are discussed and directions for future research are outlined.