The purpose of the PKM activities is to maximize the performance of principal, treasurer, administration of SMP Kota Tangerang Selatan cluster 02. The focus is on school treasurer tasked with handling the use of BOS funds. BOS Treasurer has a tax obligation that is somewhat different than the government treasurer in general. Procedure of calculation of PPh article 21 on employee's salary is derived from calculating the entire gross income of a month which includes basic salary and allowances, then reduced by the existing deduction, then calculated net income a year. The PKM research object is the principal, treasurer, administration of SMP Kota Tangerang Selatan cluster 02. The problem is derived from the lack of knowledge and the school principal, treasurer related to the tax problems in the use of BOS funds (school operational Assistance). The training Program that will be provided by experts in the field of tax is expected to provide knowledge related to tax calculation of article 21, article 23, and PPh article 4 paragraph 2 to the principal, treasurer, SMP administration of Tangerang City South Cluster 02.Keywords: Training, tax calculation of article 21, article 23, and PPh article 4 paragraph 2