No, and conflating the two is a common misconception. "Real-time" means meeting timing deadlines deterministically, which is a property you engineer and verify; an RTOS merely provides tools that make it achievable: priority-based preemption so urgent tasks run first, bounded primitive operations, and predictable scheduling. But you can absolutely build a system on an RTOS that misses deadlines, if you assign priorities wrong, overload the CPU beyond what's schedulable, hold locks too long, hit priority inversion, or let a low-priority task block a high-priority one. Conversely, a carefully written bare-metal super-loop with interrupts can be perfectly real-time for its workload. So the RTOS is necessary-ish for complex real-time systems (because hand-scheduling many tasks is infeasible) but not sufficient, you still have to choose priorities deliberately, keep critical sections short, ensure the task set is schedulable (analyze worst-case execution times and CPU utilization), and use priority-inheritance mutexes to bound blocking. Real-time is about guaranteed worst-case behavior, and that comes from design and analysis, not from linking a kernel.
RTOS & Real-Time Concepts · Interview question
Does using an RTOS make your system real-time?
A strong answer
What a weak answer sounds like
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From the lesson
Bare-Metal vs RTOS
When the super-loop stops scaling: what an RTOS buys you (tasks, priorities, blocking that yields), what it costs (RAM, complexity, concurrency bugs), and when bare-metal is still the right call.