The Luquillo Critical Zone Observatory (LCZO) is in the northeastern portion of Puerto Rico. This subtropical, humid and maritime region is one of the wettest in the Caribbean. One LCZO data set that has not been previously analyzed is ozone at the canopy level. Ozone generally has not been recorded or studied much in tropical regions of the world, but needs to be better understood since increasing numbers of people around the world will be living in the urban tropics. The data for this study has been collected since April 2008 from the Bisley Lower Tower, which also collects weather, climate and rainfall data. The purpose of this study is ultimately to understand the variations of canopy level ozone in this montane tropical rainforest. The study analyzed the ozone levels across time—hourly, monthly and seasonally. 8-hour averages were calculated to compare to US ozone standards. The ozone data was then combined with climate data to find correlations between ozone with temperature, relative humidity, precipitation, solar radiation and wind. From the results, overall the air quality of the Luquillo Mountains is good as compared to US ozone standards and to other forested or high elevation sites. The forest has plenty of VOCs, so the NOx are likely the limiting factor for ozone production, with climatic conditions also affecting the likelihood that ozone will form. Ozone varies temporally with sunlight, where it is highest at noon during each day and highest in the summer during each year. The highest ozone days did get over the US standards for ozone and occurred on hot, sunny dry days with relatively stagnant air. The air pollution that contributed the highest ozone days may not have come from one specific area, implying that pollution may be coming from many directions, which policies need to address.