Brassinosteroids (BRs) are plant steroid hormones with essential roles in a broad range of biological and developmental processes. The molecular components of canonical BR signaling pathways, including the plasma membrane-anchored co-receptor complex (BRI1 and BAK1), cytoplasmic and nuclear signal transmitters (BSK1, CDG1, BSU1, 14-3-3 proteins, BIN2, and PP2A), and key transcription factors (BZR1, BES1, and BEHs) have been well established, and recent studies have revealed the prominent roles of crosstalk between BR pathways and other signaling pathways in diverse plant developmental processes. We provide an overview of recent progress in our understanding of the biological roles of the interplay between BRs and other signaling cues, with an emphasis on how BRs regulate plant developmental programs by modulating diverse signaling pathways.