The purpose of this master's thesis is to examine the effect of older siblings on the language competence of Slovenian children in early childhood, in connection with some other factors such as parental education, the quality of the family environment and the child's gender. Sixty children (28 girls and 32 boys) participated in this study. They were between the ages of 5;0 and 5;11 and attended kindergarten in Slovenia. The children were individually tested with the Test of Storytelling: Little Glove (Marjanovič Umek, Fekonja Peklaj and Kranjc, 2010) and the Metalinguistic Awareness Scale, which is part of the Scales of General Language Development – LJ (Marjanovič Umek, Fekonja Peklaj, Podlesek, Kranjc and Bajc, 2008), while their parents completed the Home Environment Questionnaire. Child's position in the family (an only child or a child with older siblings) was found to be a good predictor of children's storytelling skills. The results showed that, in comparison with the only children, the children with older siblings demonstrated more advanced storytelling skills. The children whose mothers had received higher education achieved significantly higher scores on the Metalinguistic Awareness Scale than the children whose mothers had lower education. Metalinguistic awareness was found to be significantly connected with family material possessions (i.e. the number of books in the family home and the number of children's books). Girls and boys did not differ significantly in measures of language competence. This piece of research makes a contribution to the existing body of research on both the theoretical and practical levels, since it is the first in the Slovenian setting to study the effect of older siblings in relation to younger children's language development. The findings of the present study highlight some protective and risk factors in language development that can provide a basis for working with children in a more systematic manner.