Episodic memory is an essential cognitive function to support our everyday life. It depends on the hippocampus to bind the experienced events into their spatiotemporal contexts, i.e. giving us information about what has happened, where and when. Sleep is vital for declarative memory. Broad evidence suggests sleep as an optimal state to transfer a hippocampus-dependent memory from a temporary short-term representation into its stable neocortical long-term storage, i.e. its consolidation. This sleep-mediated consolidation process is thought to happen especially during deeper slow-wave sleep, i.e. a sleep stage most abundant in children before puberty. It is unclear how sleep consolidates particularly episodic memory, and how sleep-mediated consolidation changes during development. This dissertation aimed to establish new behavioral paradigms and study sleep’s effect on episodic memory in adults and children. We hypothesized that sleep benefits specifically the consolidation of episodic aspects of memory, especially in children. To explore sleep’s effect on episodic memory consolidation in human adults (18-37 years) and children (8-12 years) we established a new episodic task to assess “What-Where-When” memory by explicit (oral report) and implicit (eye-tracking) measures. Additionally, we changed a word-pair learning task to an item–source paradigm, in which word pairs (items) were learned in temporal contexts (source) separated by two lists. This task allowed the assessment of episodic aspects of word-pair learning, i.e. the binding of item and source memory. Using the same tasks, children and adults encoded two episodes and learned two lists of word pairs, with each episode and list being separated by an hour. Memory was then tested on short-term (1-hour delay) prior to sleep as well as after long-term retention (~10-h delay) with either a night of sleep or a day of wakefulness. In adults, explicit and implicit measures of episodic memory were positively associated with each other, and both benefitted from sleep, thus linking this sleep benefit to previous rodent studies and opening the possibility to apply this paradigm to a broader age range (study I). Comparing adults with children, both ages showed a two-fold benefit for episodic memory after sleep than after wakefulness, even though children had superior amounts of slow-wave sleep. Surprisingly, children started at a much lower episodic memory level on the short-term before sleep than adults, suggesting children had less capacity to encode or retain episodic memories. However, children did not forget the episodes any further over the any long-term retention interval as the adults did, suggesting the consolidation of episodic memory in children to be more efficient, and unrelated to sleep (study II). Replicating previous studies, we also found that children benefit from sleep for the explicitly learned word-pair memory over sleep. Unlike the weak temporal memory effect in the episodic task, we found a benefit from sleep for the temporal context memory in the word-pair learning task. Although also here the children’s capacity for episodic binding was reduced shortly after encoding (1-hour recall) as compared to adults, unlike in the episodic task, the children seemed rather to “unbind” the word-pair and temporal context memory over sleep. Moreover, children maintained semantic memory for the word pairs better on short-term, but, unlike adults, they showed forgetting over sleep. This suggests altered forgetting curves over sleep for episodic vs. semantic based memory (study III). Across studies, episodic aspects were in part positively correlated with sleep spindles (a hallmark feature of sleep) and slow-wave sleep, while semantic aspects correlated negatively with sleep spindles, suggesting different preferred roles for sleep spindles and slow-wave sleep in episodic and semantic memory consolidation. Notably, sleep more effectively consolidated the kind of memory that each age group retained worse on the short-term, e.g. the still developing episodic memory in children. Taken together, this thesis supports the hypothesis that sleep benefits the consolidation of hippocampus-dependent memory for episodes and their spatial and temporal contexts. Children’s lower capacity for episodic memories might be compensated by more effective consolidation mechanisms. The finding that deeper sleep in children might also favor unbinding of episodic memories (i.e. decontextualization) should be scrutinized in future studies.