This study is attempted to examine the effects of birth order on academic achievement motivationrnand personality. There has been a great debate among researchers regarding this area of concern.rnIt is also one of the least researched areas in Ethiopian context; hence, it gave inspiration for thernresearcher to investigate the effects of birth order on academic achievement motivation andrnpersonality of Addis Ababa University Social Science College Students. The specific objectives ofrnthis study were to investigate the effects of birth order on academic achievement motivation andrnpersonality, to examine whether a relationship exist between personality and academicrnachievement motivation and to investigate whether gender difference exist in academicrnachievement motivation .To conduct the study, Survey research design was employed on 160rnparticipants (104 male and 56 female) students from Social Science College took part in the study.rnA self report questionnaire with items background information and adopted tests that help tornmeasure academic achievement motivation and personality was used. The reliability of thernacademic achievement motivation and personality were 0.723 and 0.871 respectively. KruskalrnWallis test,Man- Whitney U test and Spearman rho were employed to analyze the data. Resultsrnshows that birth order did not have statistically significant effect both on academic achievementrnmotivation and personality. But there is a statistically significant relationship between personalityrnand academic achievement motivation. Eventually, the researcher concludes that birth order doesrnnot have a significant effect both on academic achievement motivation and personality. There arernmany factors which may influence academic achievement motivation and personality ofrnindividuals there for, further comprehensive study is recommended