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Xyloglucan endotransglycosylase/hydrolase (XTH) genes play an important role in plant resistance to abiotic stress. However, systematic studies of the response of <i>Boehmeria nivea</i> (ramie) <i>XTH</i> genes (<i>BnXTHs</i>) to cadmium (Cd) stress are lacking. We sought to identify the <i>BnXTH</i>-family genes in ramie through bioinformatics analyses and to investigate their responses to Cd stress. We identified 19 members of the <i>BnXTH</i> gene family from the ramie genome, referred to as <i>BnXTH1-19</i>, among which <i>BnXTH18</i> and <i>BnXTH19</i> were located on no chromosomes and the remaining genes were unevenly distributed across 11 chromosomes. The 19 members were divided into four groups, Groups I/II/IIIA/IIIB, according to their phylogenetic relationships, and these groups were supported by analyses of intron–exon structure and conserved motif composition. A highly conserved catalytic site (HDEIDFEFLG) was observed in all BnXTH proteins. Additionally, three gene pairs (<i>BnXTH6</i>–<i>BnXTH16</i>, <i>BnXTH8</i>–<i>BnXTH9</i>, and <i>BnXTH17</i>–<i>BnXTH18</i>) were obtained with a fragment and tandem-repeat event analysis of the ramie genome. An analysis of cisregulatory elements revealed that <i>BnXTH</i> expression might be regulated by multiple hormones and abiotic and biotic stress responses. In particular, 17 cisregulatory elements related to abiotic and biotic stress responses and 11 cisregulatory elements related to hormone responses were identified. We also found that most <i>BnXTH</i> genes responded to Cd stress, and <i>BnXTH1</i>, <i>BnXTH3</i>, <i>BnXTH6</i>, and <i>BnXTH15</i> were most likely to contribute to the Cd tolerance of ramie, as evidenced by the substantial increases in expression under Cd treatment. Heterologous expression of <i>BnXTH1</i>, <i>BnXTH6</i>, and <i>BnXTH15</i> significantly enhanced the Cd tolerance of transgenic yeast cells. These results suggest that the <i>BnXTH</i> gene family is involved in Cd stress responses, laying a theoretical foundation for functional studies of <i>BnXTH</i> genes and the innovative breeding of Cd-tolerant ramie.