In this paper, a new scheme, named after parallel quadrature index modulation (PQIM) with transmit diversity, is proposed to not only greatly increase the spectral efficiency but also achieve the transmit diversity gain for improving the bit error rate performance. Specifically, the total number of transmit antennas is grouped into multiple groups. For each group, in the in-phase dimension, two components of a three dimension (3D) constellation symbol are modulated on two active transmit antennas; in the quadrature dimension, the remaining one component of the 3D constellation symbol is modulated on only one active transmit antenna. Then, for achieving the diversity gain, each group of transmit antennas modulates an identical 3D symbol. Furthermore, the average bit error probability (BEP) is analyzed. Simulation results demonstrate the proposed PQIM outperforms other schemes in terms of BEP in wireless communication.