The authors categorized communication strategies employed to exchange social support (type and person centeredness) in three online forums about parents with harmful drinking. Data included discussion postreplies over 2 months; N = 1,644 units of analysis. Support type categories were identification, emotional, informational, network, and esteem. For person centeredness, most messages were moderate (expressed sympathy, provided distraction), followed by high (helped with feelings), and then low (minimized feelings). Adult offspring of parents with harmful drinking predominantly communicate self-interested forms of support in online forums. Based on principles of supportive communication, esteem support and high person centeredness may enhance social support in these settings.