The objective of this study is to produce a validated and reliable questionnaire that can assess the knowledge, attitudes, and practices (KAP) of Malaysian young adults towards sugar-sweetened beverages (SSB). Content validation was done using I-CVI and face validity index (FVI) was used to performed face validation. Construct validity was examined using Exploratory Factor Analysis. Cronbach’s Alpha (α) was established to determine internal reliability, and Pearson Correlation (PCs) was used to measure the inter-rater reliability of the items. Public universities in Klang Valley, Malaysia. Experts in Nutrition and Health Sciences and undergraduates aged 18 and above. I-CVI lead to the elimination of one item in the attitude domain and all items obtained satisfactory levels of FVI. The measurement of α lead to the elimination of several items and PCs indicated excellent inter-rater reliability (r > 0.7; p < 0.05) for all of the remaining items. The evidence on the validity and reliability of a questionnaire to assess KAP on SSB has been obtained. It can now be used among young adults in Malaysia.