Gifted students' often go unchallenged in the classroom, and this lack of tailored instruction can lead to decreased motivation, which, in turn, influences underachievement, which is a significant concern since these children, theoretically, should be our highest achievers. This 4-week (i.e., eight instructional days) semi-randomized, pre-test/post-test experimental design study tested a mathematical problem-solving intervention to evaluate its effects on gifted students' motivation in mathematics. Fourth and fifth grade gifted students were semi-randomly placed into groups for mathematical instruction using business-as-usual, Traditional Problem-Solving (TPS), or Mathematical Problem-Posing (MPP) pedagogical approaches. Twenty-nine gifted students took the Children's Academic Intrinsic Motivation Inventory (CAIMI; Gottfried, 2006) at pre-test (i.e., before instruction) and again at post-test to measure any potential changes in their learning motivation in mathematics using raw scores. A one-way analysis of covariance (ANCOVA) was conducted to explore the mean difference between groups (i.e., TPS/MPP instruction) on one continuous dependent variable (i.e., post-test motivation scores) while controlling for pre-test motivation scores (i.e., covariate). After controlling for pre-test scores, there was no statistically significant difference between groups in students' motivation scores, F(1, 26) = 0.057, p = 0.813, although students' motivation scores increased in both groups. Limitations, such as the duration of the intervention, are discussed along with implications for future research, which include repeating the study with a larger sample and for a longer duration. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]