Previous research has shown temperament to be stable throughout development and this effect remains when controlling for infant birth order. However, to our knowledge, there have been no investigations examining the direct relationship between temperament characteristics and birth order within the family. Because infant temperament has been shown to be related to maternal stress during pregnancy it stands to reason that mothers caring for multiple children while pregnant will experience more stress, and thus affect the temperament of their gestating offspring. Therefore, the first aim of the present investigation was to evaluate whether birth order was associated with infant temperament. Additionally, research has shown relationships between birth order and language; with second born children showing a significant advancement of language skills compared to first born children. However, no studies have investigated the relationship between birth order and gestural abilities. Because gestural abilities significantly predict language development, it stands to reason that birth order should also affect the gestural abilities of infants. Thus, the second aim of the current project was to evaluate the relationship between birth order and gestural abilities. Eighty-three children visited the lab at M = 15.45 months. Caregivers completed the Infant Behavioral Questionnaire-Revised (IBQ-R), the MacArthur-Bates Communicative Development Inventory:Words and Gestures (MCDI-WG), and a demographic questionnaire concerning family size and birth order. In line with our first aim, we evaluated correlations between infant temperament and birth order. These analyses revealed a significant relationship between the temperamental superdimension of negative affectivity; specifically, the subdimension of sadness was the main factor driving the relationship between birth order and temperament. Next, to investigate whether birth order was related to gestural abilities, we analyzed correlations between birth order and the MCDI-WG categories of performing actions with objects, as well as imitation. This analysis revealed significant associations between birth order and both gestural categories. While these results were in line with our expectations, they remain to be supported by replication. However, should these results withstand tests of replication, they suggest interesting findings for both temperament and language research. First, these results suggest that later born children are at risk for a difficult temperament; however, the specific cause of this relationship is unknown, but could include prenatal stress, or stress during infancy such as less time spent with caregivers. Secondly, these results suggest that later born children are at a particular advantage. This advantage may be due to the fact that later born children, by virtue of their larger families, have a greater number of exemplars from which to learn gestures through observation.