<p>Lignocellulosic ethanol is one of the most promising energy alternatives, which is produced employing agro-industrial wastes, such as <i>Agave tequilana</i> bagasse (ATB), an important agro-waste in Mexico generated during the agave fructans and tequila production. However, reaching high ethanol productivity from ATB requires outstanding microorganisms tolerating stressful fermentation conditions. This work evaluated the fermentative capacity of nine <i>Kluyveromyces marxianus</i> strains isolated from artisanal fermentation of mezcal, another emblematic Mexican beverage. The <i>K. marxianus</i> yeasts fermentative performance was assessed in high ATB loading enzymatic hydrolysates (20% w v^− 1), a medium with high concentrations of organic acids, furan aldehydes, phenolic compounds, as well as high solids concentration. The results showed variations in the fermentative capacities, sugar consumption rate, ethanol productivity, and ethanol yield of <i>K. marxianus</i> strains during ethanol production at 35, 38, 40, and 43&#xa0;°C. The maximum ethanol productivity observed was 1.94 ± 0.14&#xa0;g L^− 1 h^− 1 by the <i>K. marxianus</i> SLP1 strain at 38&#xa0;°C; conversely, the lowest productivity of 0.07 ± 0.00&#xa0;g L^− 1 h^− 1 was detected with the strain <i>K. marxianus</i> OFF1 at 35&#xa0;°C. Likewise, substantial differences were observed in the production profiles of volatile compounds such as acetaldehyde and isobutanol. According to the results, <i>K. marxianus</i> is a promising alternative for lignocellulosic ethanol production from ATB under high-solid loading and elevated temperature conditions.</p> Graphical Abstract <p></p>