Many studies reported that an open-ended concept map technique is a standard for reflecting learners' knowledge structure. However, little information has been provided that expands open-ended concept mapping to improve students' learning outcomes and meaningful learning. This study aimed to investigate the effects of Extended Scratch-Build (ESB) concept mapping on students' learning outcomes, consisting of understanding, map size, and quality of knowledge structure. ESB is an extended open-ended technique that requests students to connect a prior-existing original concept map with a new additional map on related material topics. ESB offers an expansion of concept maps by adding new propositions and linking them to previous existing maps to enhance meaningful learning. Twenty-five university students have participated in the present study. The collected data included a pre-test, post-test, delayed-test, map size, and quality of map proposition scores. The Wilcoxon signed-rank test was used to confirm the ESB performance. The statistical results indicated that ESB could improve meaningful learning through extended concept mapping approach and had a positive effect on students' learning outcomes. This study also emphasized that there was a correlation between the original and additional maps on students' learning outcomes.