Jen Sincero (born August 7, 1965) is an American writer, speaker, and success coach.

[3] In 2000, Sincero moved to Los Angeles, California,[3] and worked as a freelance writer, writing marketing materials for the recording industry, magazine articles, blogs and performing spoken word.

In 2005, she released her second book, The Straight Girl's Guide to Sleeping With Chicks (Simon & Schuster, 2005).

[2] In 2008, Sincero began facilitating business development workshops for the women's entrepreneurial organization, Ladies Who Launch, and later started her own practice as a success coach.

[3] Her third book, You Are A Badass: How to Stop Doubting Your Greatness and Start Living an Awesome Life (Running Press, 2013), has sold over 5 million copies, is a #1 New York Times bestseller, is available in over 40 languages and has spawned calendars, motivational buttons, day planners and the follow-up books You Are a Badass at Making Money: Master the Mindset of Wealth (Viking, 2017), which was also a New York Times bestseller, You Are a Badass Everyday: How to Keep Your Motivation Strong, Your Vibe High, and Your Quest for Transformation Unstoppable (Viking, 2018), and Badass Habits: Cultivate the Awareness, Boundaries and Daily Upgrades you Need to Make Them Stick (Viking 2020).