引导进程（英语：boot loader）位于电脑或其他计算机应用上，是指引导操作系统启动的进程。启动程序启动方式及进程视应用机型种类而不同。例如在普通的个人电脑上，引导进程通常分为两部分：第一阶段引导进程位于主引导记录（MBR），用以引导位于某个分区上的第二阶段引导进程，如NTLDR、BOOTMGR和GNU GRUB等。

BIOS开机完成后，bootloader就接手初始化硬件设备、创建内存空间的映射，以便为操作系统内核准备好正确的软硬件环境。

简单的bootloader的虚拟汇编码，如其后的八个指令：

In computing, booting (or booting up) is the initialization of a computerized system. The system can be a computer or a computer appliance. The booting process can be "hard", after electrical power to the CPU is switched from off to on (in order to diagnose particular hardware errors), or "soft", when those power-on self-tests (POST) can be avoided. Soft booting can be initiated by hardware such as a button press, or by software command. Booting is complete when the normal, operative, runtime environment is attained.