No.
The Combat section of the basic rules is pretty unequivocal about this.
Quoting the section titled "Your Turn" (emphasis in original):
On your turn, you can move a distance up to your speed and take one action.
From the rule on Extra Attack (emphasis mine):
you can attack twice, instead of once, whenever you take the Attack action on your turn.
From the rule on the Ready action (emphasis mine):
Sometimes you want to get the jump on a foe or wait for a particular circumstance before you act. To do so, you can take the Ready action on your turn, which lets you act using your reaction before the start of your next turn.
When you take the Ready action on your turn to attack using your reaction, the Extra Attack does not apply. It doesn't say "whenever you attack on your turn". It says "whenever you take the Attack action on your turn", which has a specific mechanical meaning in this context.
See the section on Actions in Combat from the Basic Rules. It's clear that:
- You get to take one action on your turn (unless a feature like Action Surge gives you more than one action).
- Whenever you take the Attack action on your turn, you can use the Extra Attack feature.
- When you take the Ready action on your turn, it doesn't allow you to use the Extra Attack feature.
Also, from the Attack action section in the combat rules:
Certain features, such as the Extra Attack feature of the Fighter, allow you to make more than one attack with this action.
The Ready action description just below that includes no mention of Extra Attack.