RankCSE is an unsupervised machine learning framework designed to generate high-quality sentence embeddings by integrating contrastive learning with learning-to-rank objectives. While standard contrastive sentence embedding methods typically treat data points in a binary manner as either similar or dissimilar, RankCSE captures more nuanced, fine-grained degrees of semantic relevance among sentences. It operates by enforcing ranking consistency between different representations of an input produced under distinct dropout masks while simultaneously distilling listwise ranking knowledge from a teacher model into the representations. This approach enables natural language processing models to produce semantically discriminative vector representations that effectively capture varying levels of semantic similarity for downstream text retrieval and evaluation tasks.