The purpose of this study is to adapt the Lifespan Sibling Relationship Scale (LSRS) developed by Riggio (2000) to Turkish. The scale with its original form in English consists of 48 items in total. The original scale was translated into Turkish by three instructors who are proficient both in the field and the language. Later, the original and Turkish form of the scale was submitted to expert opinion and the final version was issued with necessary arrangements made in line with their suggestions. In the next stage, the Turkish adaptation of the LSRS and the original scale were administered to 42 prospective English teachers in two sessions separated by an interval of two weeks, and correlations between the two administrations were calculated. The Turkish version of the LSRS was administered to a total of 804 students studying at the 9th, 10th and 11th grades at four different high schools in Karsiyaka district of Izmir. The six factor structure of the LSRS was tested by means of factor analysis method. For test-retest reliability, the scale was administered to 152 persons at an interval of three weeks and the correlation coefficient between the two administrations was calculated. Furthermore, the internal consistency of the scale was evaluated by calculating Cronbach Alpha coefficient and composite reliability coefficient. The results of the research reveal that the six factor structure of the LSRS has been verified and could be used in measurement of the quality of sibling relationships in adolescents.