Interest is swelling in gender lens investing across the globe. With this swell is an increased use of gender-related terms and concepts. Similar to many fields, the terms we use and the way we use them when we talk about gender is important and meaningful. When terms are misused, this can cause unnecessary harm. To support investors to best equip themselves with the knowledge and understanding of key concepts related to gender and gender equality, this guide pulls together a few key concepts every investor should know. All key concepts in this guide are highlighted in bold and italicized. Examples are scattered throughout, largely drawn from the work of Investing in Women, an initiative of the Australian Government. This guide is not meant to be exhaustive. It is meant to provide a starting point, or primer for investors, hopefully triggering the pursuit of additional knowledge. The concepts defined in this guide draw heavily from a variety of sources listed in the references. Users of this guide are encouraged to visit the sources listed below to develop deeper understandings of gender dynamics in their own context, as notions of gender are fluid and contextual. One of the best ways to further understanding and practice is to explore mutually beneficial collaborations with partners who have gender expertise. In gender lens investing we need to continue to work to bring gender and finance experts together to design strategies that address gender issues and advance gender equality.If you have comments on this guide or would like to see more tools like this, please reach out to the Criterion Institute at info@criterioninstitute.org.