This research surveys how parasocial interaction (PSI) affects the leadership effectiveness of nonprofit organizations (NPOs) on social media. Literature review survey derivation and propositions were proposed. The findings showed parasocial interaction mediates the impact of NPOs social media credibility (which includes reliability, credibility, and attractiveness of the information source) on NPOs' effectiveness (community Identification and citizenship behavior). This implies that parasocial interaction is crucial for nonprofit organizational effectiveness on social media and proposes NPOs’ social media engagement strategies.