Yes, Bosch and Siemens dishwashers are made by the same manufacturer. Both Bosch and Siemens are brands owned by BSH Hausgeräte GmbH, a German multinational company that is one of the world's leading manufacturers of home appliances. BSH stands for "Bosch und Siemens Hausgeräte," which translates to "Bosch and Siemens Home Appliances."
BSH Hausgeräte GmbH produces a wide range of appliances, including dishwashers, under the Bosch and Siemens brands. While the two brands have their own distinct designs and features, they share many of the same technologies and manufacturing processes due to their common ownership under BSH.