The study investigated the effect of thinking aloud and self-assessment metacognitive strategies and chemistry students’ achievement in organic compounds nomenclature in Emohua Local Government Area of Rivers State, Nigeria. The study adopted the pretest post-test non-equivalent control group design. One hundred and twenty-five (67males and 58 females) senior secondary school (SSS 2) chemistry students were drawn from three secondary schools in Emohua local government area of Rivers State. Four research questions were answered while four hypotheses were tested at 0.05 level of significance. The instrument for data collection is a 50- item objective test on organic chemistry nomenclature achievement test (OCNAT). Mean, standard deviation and effect size were used to answer the research questions while t-test and ANCOVA were used to test the hypotheses. It was found that there is significant in the achievement of students when taught with thinking aloud and self-assessment strategies. Based on the findings, it was recommended among others that thinking aloud and self-assessment should be used to teach organic compounds nomenclature. The study concludes that thinking aloud and self-assessment is an effective tool in the delivery of organic chemistry concepts to the understanding of students.