Season 4 of ALF aired on NBC from September 18, 1989 until March 24, 1990.
| Episode Number | Date Aired | Title | Production Number |
|---|---|---|---|
| 4-1 | 18 Sep 89 | Baby, Come Back (season premiere) | 4002 |
| 4-2 | 25 Sep 89 | Lies | 4003 |
| 4-3 | 2 Oct 89 | Wanted: Dead or Alive | 4004 |
| 4-4 | 9 Oct 89 | We're in the Money | 4001 |
| 4-5 | 16 Oct 89 | Mind Games | 3024 |
| 4-6 | 23 Oct 89 | Hooked on a Feeling | 4005 |
| 4-7 | 30 Oct 89 | He Ain't Heavy, He's Willie's Brother | 4006 |
| 4-8 | 6 Nov 89 | The First Time Ever I Saw Your Face | 4007 |
| 4-9 | 13 Nov 89 | Live and Let Die | 4008 |
| 4-10 | 20 Nov 89 | Break Up to Make Up | 4009 |
| 4-11 | 27 Nov 89 | Happy Together | 4010 |
| 4-12 | 4 Dec 89 | Fever | 3025 |
| 4-13 | 11 Dec 89 | It's My Party | 4012 |
| 4-14 | 8 Jan 90 | Make 'em Laugh | 4011 |
| 4-15 | 15 Jan 90 | Love on the Rocks | 4014 |
| 4-16 | 22 Jan 90 | True Colors | 4015 |
| 4-17 | 29 Jan 90 | Gimme That Old Time Religion | 4016 |
| 4-18 | 5 Feb 90 | Future's So Bright, I Gotta Wear Shades | 4013 |
| 4-19 | 12 Feb 90 | When I'm 64 | 4018 |
| 4-20 | 19 Feb 90 | Mr. Sandman | 4019 |
| 4-21 | 26 Feb 90 | Stayin' Alive | 4020 |
| 4-22 | 3 Mar 90 | Hungry Like the Wolf | 4021 |
| 4-23 | 10 Mar 90 | I Gotta Be Me | 4017 |
| 4-24 | 24 Mar 90 | Consider Me Gone (series finale) | 4022 |