In two experiments, we examined 9- to 12-year-old children’s comprehension and processing of two-clause sentences with a temporal connective (before or after) in the sentence-medial or sentence-initial position. We obtained measures of individual differences in working memory (WM) capacity and WM updating to test their contributions to comprehension. We measured the accuracy of children’s responses to the questions “What happened first?” (Experiment 1; N = 74) and “What happened last?” (Experiment 2; N = 50) as well as their sentence reading times. Together, these experiments show continued development of comprehension of temporal relations in children in upper elementary school and suggest that children’s comprehension difficulties (i.e., more comprehension errors and longer reading times) were influenced by clause salience and recency effects rather than sentence chronology or the familiarity of the connective. Our findings are consistent with a memory resource-limited account and suggest that individual differences in WM updating and WM capacity make dissociable contributions to processing and comprehension of sentences with temporal order information.