Although the past decade has witnessed a growth in research on Asian Americans’ suicide-related outcomes, previous studies have tended not to address within-group ethnic variability among Asian Americans. Therefore, this study examined ethnic differences in suicide ideation in a nationally representative sample of Asian Americans that included the six largest Asian American ethnic groups— Chinese, Filipino, Indian, Japanese, Korean, and Vietnamese Americans. Participants were 1,332 Asian American adults who participated in the National Epidemiologic Survey of Alcohol and Related Conditions. The authors found that participants who had lived a longer proportion of their lives in the United States had increased odds of lifetime suicide ideation. There were significant ethnic differences in suicide ideation rates, with Korean Americans and Indian Americans reporting the highest and lowest ideation rates, respectively. Ethnicity was also a significant moderator of the relationship between proportion of life in the United Sates and suicide ideation. The potential adverse impact of proportion of life in the United States on suicide ideation was weaker among Chinese, Japanese, Korean, and Vietnamese Americans, relative to non-Chinese, non-Japanese, non-Korean, and non-Vietnamese Asian Americans, respectively. In contrast, the association between proportion of life in the United States and suicide ideation was stronger among Indian Americans than among non-Indian Americans. These findings underscore the importance of disaggregating data on Asian American suicide-related outcomes.