Assess associations between social networks and urban American Indian/Alaska Native emerging adults' alcohol, cannabis, and opioid use and intentions. American Indian/Alaska Native participants ages 18-25 (N = 150; 86% female) were recruited across the United States from 12/20 to 10/21 via social media. Participants named up to 15 people whom they talked with most over the past 3 months and reported who (a) used alcohol and cannabis heavily or used other drugs (e.g., opioid use), (b) engaged in traditional practices, and (c) provided support. They also reported past 3-month alcohol, cannabis, and opioid use and intentions to use. Having a higher proportion of network members engaging in regular cannabis and heavy alcohol use (but not other drugs) was associated with more frequent cannabis use and stronger cannabis use intentions. Participants with higher proportions of members engaging in heavy alcohol use, regular cannabis use, or other drug use and who did not engage in traditional practices were more likely to report cannabis use and greater intentions to use cannabis and drink alcohol. In contrast, participants with higher proportions of network members engaging in traditional practices and who did not report heavy alcohol use, regular cannabis use, or other drug use were less likely to report intentions to use cannabis or drink alcohol. Findings emphasize what many studies have shown among various racial/ethnic groups-having network members who use substances increases the chance of use. Findings also highlight that traditional practices may be an important part of the prevention approach for this population. (PsycInfo Database Record (c) 2023 APA, all rights reserved).