Morphological Awareness (MA), a metalinguistic skill contributing to literacy and spelling development, has been an important area of research in psycholinguistics. Based on a systematic review, existing MA tasks have low reliability and debatable validity, which might affect replicability. Additionally, the outbreak of COVID exposed the paucity of measurement instruments for assessing morphological awareness online. Most MA tests are production-task-based, making online implementation difficult. The lack of quality measurement instruments for online studies has impeded replication in psycholinguistic studies. The current study adapts and validates three open-source morphological awareness tests for web-based experiments: The Base Form Morphology (BMorph) task, the Derived Form Morphology (DMorph) task, and the Wug test into multiple-choice measures. More than 150 L1 and L2 English-speaking adult readers of diverse language backgrounds were recruited from social media and university mailing lists by snowball sampling. We measured the participants’ test scores in our adapted MA tasks, vocabulary knowledge and reading comprehension tests. We examined the psychometric properties of our adapted MA measures, including internal consistency reliability and convergent validity using structural equation modelling (SEM). The current study would provide three adapted and validated open-source MA tasks for web applications. It would also bring researchers' attention to the issue of questionable measurement qualities in psycholinguistics. The full versions of our adapted MA tests are made publicly available on the Open Science Framework.