Indoor environments are particularly vulnerable to microplastics (MPs) and associated copollutants due to limited air circulation and particulate matter accumulation. Continuous monitoring is essential to evaluate exposure levels and health risks. We propose using indoor spider webs as passive monitors for MPs and their copollutants. MPs were found in both web and dust samples with nonuniform distribution (p < 0.05), indicating contamination hotspots. Web samples had significantly higher MP levels (138−33,570 MPs/g) compared to dust samples (59−9324 MPs/g). A strong positive correlation (r = 0.93, p < 0.05) between MPs in dust and webs suggests that spider webs are effective bioindicators of indoor MP contamination. The study also revealed the presence of Bisphenol A and various phthalic acid esters (PAEs). Co-pollutant concentrations ranged from 52.02−1971.78 μg/ kg in webs and 43.18−518.42 μg/kg in dust. Diethyl phthalate (DEP) was more common in webs, while Dibutyl phthalate (DBP) predominated in dust. These findings highlight spider webs' potential as both effective biomonitoring tools and significant sinks for MPs and their cocontaminants in indoor environments.