This study investigated the effectiveness of graphic organizers and simulation gamebased learning in teaching vocabulary as tools for enhancing students’ achievement in 21st century learning skills in Nigeria. To achieve this the study tested three research hypotheses were generated to carry out the study. A quasi- experimental pretest-posttest design was used comprising two experimental groups and one control group. Each group consisted of 80 students selected from both urban and rural areas of Ondo metropolis. The study population included all junior secondary school students in Ondo metropolis from which 240 students were selected using non-random sample technique. Vocabulary Achievement Test (VAT) and instructional packages using (graphic organizer and simulation games) were used to carry out the study. Findings revealed a significant difference between the posttest scores of students in the experimental and control group, a significant main effect of school location and students’ achievement, gender was not a determining factor of students’ achievement in the experimental and control groups. The study recommended that teachers should integrate graphic organizers and simulation games in teaching vocabulary as these can directly influence students’ learning outcome in vocabulary, English Language teachers should undergo regular training so as to be more knowledgeable about pedagogy and should always improvise relevant instructional resources that could enhance effective learning