A diet containing foods that are sources of S-methylmethionine (SMM), and its use as a dietary supplement, have demonstrated beneficial health effects. Thus, the objective of this work was to evaluate the inclusion of SMM as a dietary supplement in C57BL/6J high-fat-fed mice to verify whether this compound alone would be responsible for these positive effects. Mice were divided into three groups: LF (low-fat diet), HF (high-fat diet), and HF+SMM (high-fat diet plus SMM), and maintained for 10 weeks with water and food provided ad libitum. Body weight and food intake were measured weekly, and food efficiency was calculated. In addition, at week 9, fasting glucose was measured and, after necropsy, at week 10, liver, inguinal adipose, and kidney weights were measured; triglycerides, histology, liver gene expression, serum insulin, and MCP-1 levels were also determined. Final body weight, average weight gain, and the liver/body weight of the SMM group showed a significant difference with the LF group. HF+SMM-fed mice show improved regulation in glucose metabolism, demonstrated by the assessment of fasting glucose, insulin concentration, and HOMA-IR, compared with the HF-fed group. Liver triglycerides and MCP-1 levels showed no significant differences between fed groups. By the positive gene regulation of Sult1e1, Phlda1, and Ciart, we hypothesized that SMM administration to mice may have regulated xenobiotic, glucose, and circadian rhythm pathways.