The 2021 IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium (BCICTS) event brings together distinguished experts to present their latest results in bipolar, SiGe BiCMOS, and compound semiconductor circuits, devices, and technology. The event focuses in leading edge bipolar/BiCMOS devices and technology, 5G ICs, GaN HPAs, InP THz PAs, optical CMOS/SiGe transceivers, GaN HEMT power devices, and advances in compact modeling all presented together. It includes presentations from submissions contributed worldwide on all aspects of these technologies. Topics span process technology, device advances, TCAD modeling, compact modeling to IC design and testing, high-volume manufacturing, and system applications. BCICTS 2021 will also feature the very latest results in RF/ microwave, millimeter-wave, THz, analog mixed signal, and optoelectronic integrated circuits. As a complement to the technical program, the symposium includes numerous social events that allow participants to interact and network in a friendly, relaxed setting.