The prevalence of obesity has significantly increased worldwide. Therefore, this study aimed to evaluate the influence of obesity in the proteomic profile of periodontal ligament (PDL) tissues of rat first maxillary molars submitted to orthodontic tooth movement. The study was approved by the Ethical Committee on Animal Experimentation of the Sao Paulo State University, School of Dentistry at Araraquara, Brazil (protocol number 16/2015) and followed the Animal Research: Reporting of In Vivo Experiments guidelines. Therefore, for this study, we used ten male adult Holtzman rats (weight average – 300 g, approximately 8 weeks old). Animals were randomly assigned to one of the following experimental groups: 1 – M group: animals received a standard diet and 75 days after that, the first maxillary molar was randomly selected to be submitted to OTM for 15 days (n=5), and 2 – OM group: animals received a high-fat diet to induce obesity, and 75 days after that the first maxillary molar was randomly selected to be subjected to OTM for 15 days (n=5). All animals were kept under controlled temperature (22-25 °C), receiving water ad libitum with a 12-hour light/dark cycle. To induce obesity, animals of the OM group received a high-fat diet. In contrast to the standard diet (Labina/Purina, Ribeirão Preto, Brazil) administered to the M group. The high-fat diet contained around 3.82 kcal/g and was composed of 27.5 % of standard rat chow plus 25 % of peanuts, 25 % of milk chocolate, and 12.5 % sweet biscuits and contained 20 g of protein, 48 g of carbohydrate, 20 g of total fat, and 4 g of fiber per 100 g of diet. This feed was daily replaced and had started 75 days before baseline (M initiation). The procedure to induce OTM was by a closed coil nickel-titanium spring (Sentalloy, GAC Central Slip, New York, EUA) connected the maxillary first molar and central incisors with a steel wire (CrNi, 0.20 mm, 55.01.208; Morelli, Sorocaba, Brazi). Fifteen days after OTM, animals were euthanized by anesthetic overdose.