PREHEAT OVEN TO 350ºF.
GRIND GRAHAM CRACKERS IN A FOOD PROCESSOR UNTIL FINE CRUMBS FORM. OR PLACE CRACKERS IN A RESEALABLE PLASTIC BAG AND CRUSH WITH A ROLLING PIN. PLACE CRUMBS IN A SMALL BOWL.
MELT BUTTER ON STOVE TOP OR IN MICROWAVE AND POUR OVER GRAHAM CRACKER CRUMBS, MIXING WITH A FORK UNTIL COMPLETELY MOISTENED. PRESS CRUMBS EVENLY ONTO BOTTOM OF A 9-INCH PIE PAN; PLACE CRUST IN REFRIGERATOR WHILE PREPARING LEMON FILLING.
IN A MEDIUM BOWL, COMBINE CONDENSED MILK AND EGGS; MIX UNTIL SMOOTH. ADD LEMON JUICE AND ZEST; STIR UNTIL INCORPORATED AND POUR INTO PREPARED CRUST.
BAKE PIE FOR 15 MINUTES. COOL COMPLETELY AND FOR BEST FLAVOR, SERVE CHILLED. YIELDS 1 PIECE PER SERVING.
