Unhealthy weight control behaviors (UWCBs) have been decreasing for most youth over time, yet little is known whether these behaviors have changed for sexual minority (e.g., non-heterosexual) youth. This is important because many studies have found that sexual minorities report some of the highest rates of UWCBs. To determine whether or not these behaviors have changed over time, given the extreme changes in social contexts over the past two decades, we utilised three waves of the Minnesota Student Survey (N = 55,597, M_age = 17). In doing so, we report trends, disparities, and changes in disparities of UWCBs. Overall, the prevalence of UWCBs has declined from 1999 to 2010 for all youth, but there are alarming disparities by sex of sexual partner. We found that both- and same-sex partnered male youth were more likely to fast, use diet pills, and vomit on purpose to lose weight compared to their opposite-sex partnered counterparts in all three survey years; specifically, both-sex partnered boys were up to 5.5× as likely to vomit on purpose compared to their opposite-sex partnered counterparts. Likewise, both-sex partnered girls were more likely to use diet pills and vomit on purpose to lose weight compared to opposite-sex partnered girls in all three survey years. Additionally, the disparity in fasting to lose weight widened for the same-sex partnered females compared to the opposite-sex partnered females from 1998 to 2004. This has implications for UWCB interventions and preventions targeted specifically towards sexual minorities.