The first-line treatment for knee osteoarthritis (KOA) in terms of pain and functionality is physical exercise. The use of interferential current (IC) associated with other resources may be beneficial in reducing pain intensity and improving functionality. However, the effects of its simultaneous use with therapeutic exercise have not yet been fully established. The aim of this project will be to evaluate the effects of including IC in a therapeutic exercise program in relation to pain intensity, functionality, self-efficacy, maximum voluntary contraction and overall perceived effect in individuals with KOA. Therefore, research participants of both sexes, between 40 and 75 years old, with a clinical diagnosis of unilateral KOA, who have knee pain for more than 3 months, with a minimum score of 3 points on the numerical pain scale, morning stiffness for less than 30 minutes, crepitation, bone sensitivity and absence of palpable heat will be recruited. The research participants will be randomized into three groups: therapeutic exercises (n=42) and therapeutic exercises + IC (n=42) and therapeutic exercises + IC placebo. Eight consecutive weeks of treatment will be carried out. The research participants will be evaluated before the intervention, after the end of the intervention of eight consecutive weeks of intervention and after four weeks at the end of the last week of intervention, through the instruments: numeric pain scale (NPS), Knee Injury and Osteoarthritis Outcome Score (KOOS), patient-specific functional scale (EFEP), Pain self-efficacy questionnaire (PSEQ), maximum voluntary isometric contraction (MVIC), 30-second sit-to-stand test (TSL30s), global perception scale (EPG). For data analysis, a normality test will be used to verify the distribution of the data and a statistical test appropriate for the appropriate intra and inter-group comparisons, thus considering two factors in the comparisons, time and group. A significance level of 5% will be adopted.