An important skill in solving problems, especially ill-structured problems, is the production of coherent arguments to justly solutions and actions. Because direct instruction in argumentation has produced inconsistent results and cannot effectively support online learning, we examined the use of online argumentation scaffolds to engage and support coherent argumentation. In this study, we showed that providing a constraint-based argumentation scaffold during group problem-solving activities increased the generation of coherent arguments. The same scaffold further resulted in significantly more problem-solving actions during collaborative group discussions. The effects of the scaffold varied for problem type. Groups that solved ill-structured problems produced more extensive arguments. When solving ill-structured problems, students need more argumentation support because of the importance of generating and supporting alternative solutions. The close relationship between argumentation and problem solving, especially ill-structured problem solving, is significant. The effects of the argument scaffold consistently transferred to the production of arguments during individual problem solving. Students used the familiar argumentation scripts while solving problems individually.