Ketu in the 3rd house (Sahaja, the house of courage) brings the significations of Ketu, namely spirituality & moksha, detachment, past-life karma, into the area of courage, self-effort, siblings and communication. The 3rd house governs courage & effort, younger siblings, communication & skills, short journeys.
Results of Ketu in the 3rd House
Ketu is a malefic planet, so here it tends to bring confusion, sudden losses, feeling lost, and unexplained anxieties focused on courage, self-effort, siblings and communication.The exact result depends on which sign Ketu occupies here and the aspects it receives.
When It Activates
These results typically surface during the Vimshottari mahadasha or antardasha of Ketu, and when transiting planets trigger the 3rd house. A well-placed Ketu here supports bravery, initiative, talent and good bonds with siblings; when afflicted it can indicate timidity, lack of drive and strained sibling relationships.