The objective of this study was to assess factors associated with later acquisition of English language fluency among Hmong refugees in Minnesota. Fluency in a society's lingua franca is a critical skill in psychosocial adaptation and mental health. A longitudinal study design was used, in which premigration and early postmigration factors were related to subsequent English fluency. The first group of 102 Hmong refugees located in Minnesota by the Immigration and Naturalization Service participated, and were interviewed in their homes. Hmong research assistants collected data using a questionnaire format at 1.5 years following resettlement in the U.S. Eight years later, two measures of English language competence were obtained: a self-assessment and an objective measure of English language fluency. Self-assessed fluency and performance on a brief English test showed good correlation. Greater English fluency on both measures was predicted by the following: younger age, male gender, education or vocational training in Laos prior to migration, occupation in Laos requiring literacy, study of English while in Asia, less proximity to other Hmong households in the U.S., any educational involvement in the U.S. (except English as a second language or ESL training), and not receiving welfare. Self-assessment of English fluency appeared to be a valid measure of competence in English. Demographic characteristics, certain premigration experiences, and early postmigration experiences predicted English fluency after 10 years in the U.S. ESL training was not associated with eventual English fluency on either self-assessment or objective testing. Recommendations are made to enhance English fluency, and hence the psychosocial adaptation of refuguees and other immigrants to the U.S.