Background: The population of Ethiopia is very young, with a median age of approximately 17.1 years, according to the 2007 Population and Housing Census of Ethiopia. Young people age 15-24 represented about 14 percent of the population, according to the 1984 Population and Housing Census, but by the time of the 2007 Population and Housing Census, this percentage had grown to 20 percent. In 1984 adolescent women accounted for about one-fifth of all women of reproductive age (age15-49); by 2007, they accounted for 25 percent. Similarly, the share of young women (age 20-24) among all women of reproductive age (age 15-49) increased from 17 percent in 1984 to 19 percent in 2007. The 2011 Ethiopia Demographic and Health Survey (EDHS) reports that approximately a quarter of all pregnant young women age 15-24 feel that their pregnancies are mistimed or unwanted. Studies show that complications related to pregnancy and childbirth are among the leading causes of death worldwide for adolescent girls age 15-19. In Ethiopia, where early marriage and early sexual activity in marriage are prevalent, family planning gives couples the ability to limit the number and spacing of their children, potentially lowering the death rate for women in this age group. Methods: Levels and trends in unmet need for family planning were examined, and results were compared for women age 15-24 and age 25-49. Pooled data from 2000, 2005, and 2011 EDHS surveys were used to conduct multinomial logistic regression analysis of factors associated with unmet need (for spacing and limiting) versus met need among currently married women age 15-24 and age 25-49. The study sample consisted of 7,170 women age 15-24 and 20, 773 women age 25-49. Results: The analysis shows that unmet need for family planning has decreased over time as contraceptive use has risen. From 2000 to 2011, unmet need for spacing among currently married women age 15-19 dropped from 37 percent to 32 percent; among women age 20-24, unmet need dropped from 39 percent to 22 percent; and, among women age 25-49, unmet need fell from 36 percent to 26 percent. Multivariate analysis indicates that women in rural areas (age groups 15-24 and 25-49) show high levels of unmet need compared with women in urban areas. A significant decline in unmet need (both for spacing and for limiting) was observed in 2011 for both cohorts (age groups 15-24 and 25-49). Among women age 25-49, religion, a visit by a family planning worker, a visit to a health facility, exposure to family planning from media, and an educational difference between a husband and wife were significant predictors of unmet need for spacing. Rural residence, education, religion, and exposure to mass media family planning messages were significant predictors of unmet need for limiting. Among women age 15-24, rural residence, secondary or higher level of education, and a husband with more education than his wife were significant predictors of unmet need for spacing. Educational attainment up to the primary level, religion, and exposure to mass media family planning messages were significant predictors of unmet need for limiting.