Siebel Systems, Inc., founded in 1993 by Thomas Siebel in San Mateo, California, focuses on designing and developing enterprise application software. The company's core mission is to provide comprehensive customer relationship management (CRM) solutions that help organizations manage their customer interactions efficiently. Siebel Systems offers a range of products including sales, marketing, and customer service applications, targeting large enterprises across various industries.

Notable figures associated with Siebel Systems include its founder, Thomas Siebel, who played a significant role in the company's growth and innovation. The company attracted investments from prominent venture capital firms and experienced rapid growth in the late 1990s and early 2000s. Key achievements include becoming a leader in the CRM market and being acquired by Oracle Corporation in 2005. Siebel Systems has had a lasting impact on the CRM industry, setting standards for customer relationship management software and influencing subsequent developments in the field.