Quasi-orthogonal space-time block codes with orthogonal frequency division multiplexing (QO-STBC-OFDM) can exploit multipath diversity and achieve spectrally efficient communications. However, future wireless communication systems must be robust against both unintentional and intentional interference. As a result, there is a need for proper analytical tools to assess the performance of QO-STBC-OFDM in the presence of partial-band noise jamming. First, analytical expressions for the exact pairwise error probability (PEP) of the QO-STBC-OFDM system is derived using the moment generating function (MGF). Second, the PEP is calculated under various situations, and the closed-form expressions and union bound for the bit error probability (BEP) are derived. Finally, simulations are performed and compared with the theoretical results.