LLM-based text augmentation is a machine learning data enhancement technique that uses large language models to generate diverse variations of existing textual data while preserving its core semantic meaning. By leveraging the generative capabilities of language models, this approach automatically creates paraphrases, rewrites, and stylistic reformulations that introduce varied vocabulary and grammatical structures into a dataset. It is widely employed in natural language processing and multimodal learning workflows to increase data diversity, prevent model overfitting, and improve generalization across downstream tasks without requiring manual data labeling.