High nighttime ozone (O3) concentration levels were observed in Kemaman, Terengganu, and results were compared with those in other places in Malaysia. In this study, the contribution of precursors [nitric oxide (NO) and nitrogen dioxide (NO2)] and meteorological factors wind speed, and wind direction) toward long-term high nighttime O3 over the period of 1999 to 2010 was evaluated. During this period, the recorded highest nighttime O3 ground level was 89 ppb with more than 25% surpassing 20 ppb. Analysis shows that minimal decreasing trends were measured in Kemaman. Lower nitrogen oxide (NOx) concentrations restricted the sinking agents; thus, reducing the depletion rates allowed O3 to remain in the atmosphere. Minimal associations were observed between the O3 concentration level and the speed and direction of wind. Accordingly, the largest contributor toward high nighttime O3 ground level concentration in Kemaman was most probably NOx concentration.