Children employ different types of humor as they explore, interpret, and negotiate their environments. Whereas an appreciation of verbal incongruity has been a hallmark of older preschooler humor (e.g., McGhee, 1989), more recently, other violations of expectations and clowning also have been identified as ubiquitous during the first two years of life (e.g., Loizou, 2005; Reddy, 2001). We examined the pragmatics of one 30-month-old girl's humor, and determined how it interactively harnessed the cognitive, linguistic, and socio-emotional resources available to her negotiations within her familial context. Using the methodology of a Day in the Life of a toddler in early childhood (Gillen et al., 2006), the child's entire waking day was videotaped, and all interactions were transcribed and analyzed. We identified many instances of humor, and categorized them into four major types: clowning, teasing, jokes and playful language, and physical actions. Humor served both socio-emotional and cognitive-linguistic functions, and we confirmed Reddy's (2001) finding that early humor is interpersonally co-constructed: When humor operates within the child's inter-mental development zone (Mercer, 2000), it serves to inform her or his intra-mental growth; the inter-mental precedes and enables the intra-mental. (Contains 1 note and 2 tables.)