To determine agreement among the most commonly used methods for assessing the gingival biotype. An electronic survey was sent to a sample of dentists practicing in Spain. The questionnaire was based on the evaluation of 5 cases involving different gingival biotype assessment methods. Dentists were required to classify the cases as having a ?thin?, ?thick? or ?not able to classify? biotype. Each case was assessed using a frontal intraoral photo of the anterior teeth; an enlarged photo of the buccal aspect of the tooth with a periodontal probe inserted inside the sulcus; and the real thickness measured in mm with a calibrated needle. Agreement among the classifications was assessed using Cohen?s kappa coefficient. A total of 104 surveys were analyzed. The most commonly used assessment method was visual evaluation of the morphology of the gingiva and the teeth (62.5%). Concordance among the three different methods was weak (kappa = 0.278). Agreement among the classification methods was greater in extreme cases (thinner and thicker gingival thickness). The most commonly used methods for assessing gingival biotype are not reliable. The three tested methods show poor to weak agreement, which leads to non-reliable estimation of the gingival biotype.