Certainly. The 5150 and 5160 could support 4 floppies as a standard configuration via the external drive connector on the floppy controller bracket.
On later systems with DTC or Ultrastor SCSI controllers for example, could support three (with a driver) on a single cable. Some versions of DTC controllers could even support four on one "flat" cable. N.B. you needed drivers for both of these.
Some third-party floppy controllers, such as Micro Solutions (Compaticards), DTK, Western Digital WD-1002 FOX, could support 4 drives and had their own BIOS extensions to do so.
There are also floppy controllers that support secondary I/O ports with their own drivers and BIOSes. I've got a 386 tower here, for example, with 6 floppy drives in it for duplicating. Each controller uses a different I/O port, DMA and interrupt, so up to 3 floppies can be accessed simultaneously. Very cool for copying to be able to write 3 floppies at the same time.