<![CDATA[Abstrak. Kesepian (loneliness) pada mahasiswa merupakan persoalan psikologis yang serius, sebab banyaknya relasi sosial tidak selalu menjamin terpenuhinya kebutuhan akan kedekatan emosional. Penelitian sebelumnya banyak menemukan hubungan langsung antara kualitas pertemanan dan kesepian, namun belum banyak menjelaskan mekanisme psikologis di baliknya, sehingga self-disclosure diposisikan sebagai variabel mediator. Penelitian ini bertujuan menguji pengaruh kualitas interaksi pertemanan terhadap loneliness pada mahasiswa di Kota Bandung, dengan self-disclosure sebagai mediator. Penelitian menggunakan pendekatan kuantitatif desain eksplanatori pada 385 mahasiswa berusia 18-25 tahun di Kota Bandung yang dipilih melalui convenience sampling. Kualitas interaksi pertemanan, loneliness, dan self-disclosure diukur masing-masing dengan Friendship Quality Scale, UCLA Loneliness Scale, dan Revised Self-Disclosure Scale. Data dianalisis menggunakan SEM-PLS dengan SmartPLS 4 dan bootstrapping 5.000 sampel. Hasil menunjukkan kualitas interaksi pertemanan berpengaruh negatif signifikan terhadap loneliness (T = 2,638; p = 0,008) dan positif signifikan terhadap self-disclosure (T = 7,613; p < 0,001); self-disclosure berpengaruh negatif signifikan terhadap loneliness (T = 3,117; p = 0,002) dan terbukti memediasi pengaruh kualitas interaksi pertemanan terhadap loneliness (koefisien tidak langsung = -0,090; T = 2,893; p = 0,004; BC CI 95% = -0,161 hingga -0,036). Meskipun mayoritas mahasiswa berada pada kategori kualitas pertemanan dan self-disclosure yang tinggi, mayoritas juga tetap berada pada kategori loneliness yang tinggi, temuan yang dijelaskan melalui kesenjangan antara luas (breadth) dan kedalaman (depth) keterbukaan diri sesuai Social Penetration Theory. Temuan ini menegaskan bahwa mengurangi kesepian mahasiswa membutuhkan keberanian membuka diri secara mendalam, bukan sekadar memperbanyak relasi pertemanan. Abstract. Loneliness among university students is a serious psychological concern, since numerous social relationships do not guarantee emotional closeness. Prior studies have largely linked friendship quality directly to loneliness, but rarely explained the underlying mechanism, so self-disclosure is positioned as a mediator. This study examined the effect of friendship interaction quality on loneliness among university students in Bandung City, with self-disclosure as a mediator. This quantitative, explanatory study involved 385 students aged 18-25 in Bandung City, selected through convenience sampling. Friendship interaction quality, loneliness, and self-disclosure were measured with the Friendship Quality Scale, UCLA Loneliness Scale, and Revised Self-Disclosure Scale. Data were analyzed using SEM-PLS with SmartPLS 4 and 5,000-sample bootstrapping. Results showed friendship interaction quality had a significant negative effect on loneliness (T = 2.638; p = 0.008) and a significant positive effect on self-disclosure (T = 7.613; p < 0.001); self-disclosure had a significant negative effect on loneliness (T = 3.117; p = 0.002) and significantly mediated the effect of friendship interaction quality on loneliness (indirect coefficient = -0.090; T = 2.893; p = 0.004; BC CI 95% = -0.161 to -0.036). Although most students scored high on friendship quality and self-disclosure, most also remained highly lonely, a finding explained by the gap between breadth and depth of self-disclosure per Social Penetration Theory. These findings confirm that reducing loneliness requires the courage to disclose oneself more deeply, not merely expanding the number of friendships.]]>
