Social relationships are often touted as critical for well-being. However, the vast majority of studies on social relationships have relied on self-report measures of both social interactions and well-being, which makes it difficult to disentangle true associations from shared method variance. To address this gap, we assessed the quantity and quality of social interactions using both self-report and observer-based measures in everyday life. Participants (N = 256; 3,206 observations) wore the Electronically Activated Recorder (EAR), an unobtrusive audio recorder, and completed experience sampling method self-reports of their momentary social interactions, happiness, and feelings of social connectedness, 4 times each day for 1 week. Observers rated the quantity and quality of participants' social interactions based on the EAR recordings from the same time points. Quantity of social interactions was robustly associated with greater well-being in the moment and on average, whether they were measured with self-reports or observer reports. Conversational (conversational depth and self-disclosure) and relational (knowing and liking one's interaction partners) aspects of social interaction quality were also generally associated with greater well-being, but the effects were larger and more consistent for self-reported (vs. observer-reported) quality variables, within-person (vs. between-person) associations, and for predicting social connectedness (vs. happiness). Finally, although most associations were similar for introverts and extraverts, our exploratory results suggest that introverts may experience greater boosts in social connectedness, relative to extraverts, when engaging in deeper conversations. This study provides compelling multimethod evidence supporting the link between more frequent and deeper social interactions and well-being. (PsycInfo Database Record (c) 2021 APA, all rights reserved).