These Guidelines are designed to assist our colleagues in humanitarian and development contexts who conduct or manage investigations into serious allegations, including sexual exploitation and abuse (SEA) as well as allegations of fraud and corruption committed by humanitarian and development staff. These guidelines have been written for use in a wide variety of organisations, regardless of size, nationality and area of expertise. However, it is recommended that potential users have experience within the field of investigations and a familiarity with the key international standards on preventing sexual exploitation, abuse, fraud and corruption as well as other protection policies. The translation into Ukrainian has been possible thanks to the Polish PSEA Network's support.