Why is my iPod touch 5th generation so slow on wifi vs my iPhone 5s on same wifi?

How are you comparing the speed on the two devices?

You can try:

- Reset the iOS device. Nothing will be lost

Reset iOS device: Hold down the On/Off button and the Home button at the same time for at

least ten seconds, until the Apple logo appears.

- Power off and then back on your router

.- Reset network settings: Settings>General>Reset>Reset Network Settings

- iOS: Troubleshooting Wi-Fi networks and connections

- Restore from backup. See:

iOS: How to back up

- Restore to factory settings/new iOS device.