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Flowering time is a key agronomic trait, directly influencing crop yield and quality. Many flowering-time genes have been identified and characterized in the model plant <i>Arabidopsis thaliana</i>; however, these genes remain uncharacterized in many agronomically important <i>Brassica</i> crops. In this study, we identified 1064, 510, and 524 putative orthologs of <i>A.</i> <i>thaliana</i> flowering-time genes from <i>Brassica napus</i>, <i>Brassica rapa,</i> and <i>Brassica oleracea</i>, respectively, and found that genes involved in the aging and ambient temperature pathways were fewer than those in other flowering pathways. Flowering-time genes were distributed mostly on chromosome C03 in <i>B. napus</i> and <i>B. oleracea</i>, and on chromosome A09 in <i>B. rapa</i>. Calculation of non-synonymous (<i>Ka</i>)/synonymous substitution (<i>Ks</i>) ratios suggested that flowering-time genes in vernalization pathways experienced higher selection pressure than those in other pathways. Expression analysis showed that most vernalization-pathway genes were expressed in flowering organs. Approximately 40% of these genes were highly expressed in the anther, whereas flowering-time integrator genes were expressed in a highly organ-specific manner. Evolutionary selection pressures were negatively correlated with the breadth and expression levels of vernalization-pathway genes. These findings provide an integrated framework of flowering-time genes in these three <i>Brassica</i> crops and provide a foundation for deciphering the relationship between gene expression patterns and their evolutionary selection pressures in <i>Brassica napus</i>.