Simple RAW for 5e V: The Disadvantage Strikes Back

[Hairfish]

Q416:

If a creature leaves the melee range of a familiar, does the familiar get an opportunity attack?

If the Familiar is a pact of the Chain Warlock's Imp does that change things (they can attack IF you take the attack action and forgo one of your attacks)?

Does your chain pact familiar require the investment of the chain master to gain the opp attack ability?

A416:

Per the text of Find Familiar, familiars cannot make attacks, so they cannot make opportunity attacks.

Chain/Investment warlocks gain the ability to allow their familiar to make an attack under very specific circumstances. This does not grant the familiar the ability to make attacks under other circumstances, such as those that would allow opportunity attacks from normal creatures.