John Bulmer Hobson (1883 - 1969) was a leading member of the Irish Volunteers and the Irish Republican Brotherhood (IRB) before the Easter Rising in 1916. Though he was a member of the organisation that planned the Rising, he was opposed to it being carried out, and attempted to prevent it.
He is also notable for swearing Patrick Pearse into the IRB in late 1913.
Though he remained a member of the IRB, like Volunteers chief-of-staff, Eoin MacNeill, he was kept unaware of the plans for the Rising. Though he could detect underground preparations, he had no certain evidence.
He would later be told by Volunteers officers J. J. O'Connell and Éimer Duffy that the Volunteers had received orders for the Rising, timed for Easter Sunday, and he subsequently alerted MacNeill about what the IRB had planned. MacNeill issued a countermanding order, which meant that most Volunteers did not take part.
Hobson was kidnapped by the organisers of the rising to stop him from spreading news of MacNeill's order, and was held in a safehouse in Phibsboro until the Rising was well underway.