The use of medicinal plants has been well documented for the past several decades. Plants from the Lavender genus are used for culinary purposes, but also as a part of herbal medicine, owing its benefits to essential oils and bioactive compounds. A detailed description of the extraction process dynamics is required to obtain the highest possible amount of bioactive compounds from lavender. In this study, a solid-liquid extraction of lavender flowers, using water as solvent, was performed. Total polyphenols, dry matter, conductivity, and total dissolved solids were determined in regular time intervals and experimental data was further used for mathematical modelling. Peleg’s, Page’s, and the logarithmic model were applied in order to describe the kinetics of bioactive compounds in lavender during solid-liquid extraction. The initial extraction rate and extraction capacity were determined for three different extraction temperatures; T = 40, 60, and 80 °C. The obtained results indicated that the initial extraction rate and the extraction capacity were the highest at T = 80 °C. The adequacy of the applied mathematical models was estimated based on R2 and SRMSE values, which indicated that the most adequate model for solid-liquid extraction of lavender was the Peleg’s model (R2 = 0.996, for total polyphenols at T = 40 ºC and R2 = 0.975 for dry matter at T = 60 °C, respectively).