Technologies for system management interrupt (“SMI”) handling include a number of processor cores configured to enter a system management mode (“SMM”) in response to detecting an SMI. The first processor core to enter SMM and acquire a master thread lock sets an in-progress flag and executes a master SMI handler without waiting for other processor cores to enter SMM. Other processor cores execute a subordinate SMI handler. The master SMI handler may direct the subordinate SMI handlers to handle core-specific SMIs. The multi-core processor may set an SMI service pending flag in response to detecting the SMI, which is cleared by the processor core that acquires the master thread lock. A processor core entering SMM may immediately resume normal execution upon determining the in-progress flag is not set and the service pending flag is not set, to detect and mitigate spurious SMIs. Other embodiments are described and claimed.