Background and aims <p>More cases of thyroid micro-nodules have been diagnosed annually in recent years because of advancements in diagnostic technologies and increased public health awareness. To explore the application value of various machine learning (ML) algorithms based on dual-layer spectral computed tomography (DLCT) quantitative parameters in distinguishing benign from malignant thyroid micro-nodules.</p> Methods <p>All 338 thyroid micro-nodules (177 malignant micro-nodules and 161 benign micro-nodules) were randomly divided into a training cohort (<i>n</i> = 237) and a testing cohort (<i>n</i> = 101) at a ratio of 7:3. Four typical radiological features and 19 DLCT quantitative parameters in the arterial phase and venous phase were measured. Recursive feature elimination was employed for variable selection. Three ML algorithms—support vector machine (SVM), logistic regression (LR), and naive Bayes (NB)—were implemented to construct predictive models. Predictive performance was evaluated via receiver operating characteristic (ROC) curve analysis.</p> Results <p>A variable set containing 6 key variables with “one standard error” rules was identified in the SVM model, which performed well in the training and testing cohorts (area under the ROC curve (AUC): 0.924 and 0.931, respectively). A variable set containing 2 key variables was identified in the NB model, which performed well in the training and testing cohorts (AUC: 0.882 and 0.899, respectively). A variable set containing 8 key variables was identified in the LR model, which performed well in the training and testing cohorts (AUC: 0.924 and 0.925, respectively). And nine ML models were developed with varying variable sets (2, 6, or 8 variables), all of which consistently achieved AUC values above 0.85 in the training, cross validation (CV)-Training, CV-Validation, and testing cohorts.</p> Conclusions <p>Artificial intelligence-based DLCT quantitative parameters are promising for distinguishing benign from malignant thyroid micro-nodules.</p>