Many sexual and gender minority youth (SGMY) experience bias-based bullying (i.e., bullying related to their minoritized social identities) at school. Compared to their straight and cisgender peers, SGMYs also report a disproportionately high prevalence of suicidal thoughts. This study used a sizeable, racially diverse, statewide sample of secondary-aged SGMY and straight/non-transgender peers (n = 74,501) drawn from 381 comprehensive high schools. We explored the moderating role of "covitality," a construct representing the co-occurrence of youth psychological strengths, in the relationship between suicidal thoughts and homophobic and gender-based bullying experiences among SGMY. Compared to all other groups, students with two minoritized identities (i.e., both transgender and sexual minority) report the highest rates of bias-based bullying and suicidal thoughts. Mixed-effects logistic regression analyses indicate that, for most SGMY groups, increases in covitality were associated significantly with decreases in the likelihood of suicidal thoughts. However, no significant moderating effects were found, suggesting that the psychological impacts of bias-based bullying are difficult to counteract through the cultivation of psychological strengths alone. We detail the relationship between bias-based bullying and suicidal thoughts as it varies across types of bias-based bullying experiences, levels of covitality and SGMY identities.