Siebel may refer to:
Companies Siebel, a German aircraft manufacturer founded in 1937 in Halle an der Saale Siebel Systems, a software company principally engaged in the design, development, marketing and support of customer relationship management (CRM) applications.
People Carl Siebel (1836–1868), German merchant and poet
Fritz Siebel (1913–1991), Austrian American illustrator Jennifer Siebel Newsom (born 1974), American documentary filmmaker and First Lady of California since 2019 Pablo Siebel (born 1954), Chilean painter Paul Siebel (born 1937), American singer-songwriter and guitarist Theodor Siebel (1897–1975), German politician Thomas Siebel (born 1952), American business executive Tillmann Siebel (1804–1875), German revival preacher in the Siegerland Wigand Siebel (1929–2014), German sociologist A character in the opera Faust
Siebels may refer to: George G. Siebels, Jr. (1913–2000), first Republican Mayor of Birmingham, Alabama Jon Siebels, (born 1979), guitarist in the band Eve 6 Paul Siebels (born 1912), Belgian rower Wiard Siebels (born 1978), German politician