Betty (Katarina Elisabeth) Ehrenborg, as married Posse af Säby, (22 July 1818 – 22 July 1880), was a Swedish writer, psalm writer and pedagogue. She is regarded as the founder of the Swedish Sunday school. She was the daughter of the noble Casper Ehrenborg and Anna Fredrica Carlqvist and married in 1863 to Baron Johan August Posse.
Betty Ehrenborg worked as a governess in 1846–1848. In 1852–1853, she studied at the British and foreign school in London. She founded and managed a Sunday school on her brother's estate in 1855–1856.