The Machine Learning from User Interactions (MLUI) workshop seeks to bring together researchers to share their knowledge and build collaborations at the intersection of the Machine Learning and Visualization fields, with a focus on learning from user interaction. Rather than focusing on what visualization can do to support machine learning (as in current Explainable AI research), this workshop seeks contributions on *how machine learning can support visualization*. Such support incorporates human-centric sensemaking processes, user-driven analytical systems, and gaining insight from data. Our intention in this workshop is to generate open discussion about how we currently learn from user interaction, how to build intelligent visualization systems, and how to proceed with future research in this area. We hope to foster discussion regarding systems, interaction models, and interaction techniques. Further, we hope to extend last year’s collaborative creation of a research agenda that explores the future of machine learning with user interaction. For our workshop poster session, we invite both late-breaking work and contributions in this area from other research domains to submit extended abstracts between 2 and 4 pages in length (NOT including references). All submissions must be formatted according to the VGTC conference style template <http://junctionpublishing.org/vgtc/Tasks/camera.html> (i.e., NOT the journal style template that full papers use). Extended abstracts are to be submitted via email to our GMail account: learningfromusersworkshop@gmail.com. All abstracts accepted for presentation at the workshop will be linked from the workshop website. All abstracts should contain full author names and affiliations. If applicable, a link to a short video (up to 5 min. in length) may also be submitted. The abstracts will be juried by the organizers and selected external reviewers and will be chosen according to relevance, quality, and likelihood that they will stimulate and contribute to the discussion. *Submission deadline:* August 20, 2019 *Author notification:* September 1, 2019 *Camera-ready deadline:* October 1, 2019 *Workshop:* October 20, 2019 More info, posters, and papers from MLUI 2018 can be found at: https://learningfromusersworkshop.github.io/workshop2018.html