Preheat oven to 225°F. Sterilize jars for at least 10 minutes in preheated oven and keep warm until ready to use.
Sterilize the lids and rings in boiling water for at least 5 minutes.
Place the strawberries, jalapeños, lemon juice, and pectin into a large saucepan, and bring to a boil over high heat. Stir in the sugar, return to a boil, and cook for 1 minute.
Pour the jam into the hot, sterilized jars, filling to 1/4 inch from the top. Using a wet paper towel, wipe the jar rims to remove any residue. Top with dried lids, and screw on rings.
Place a canning rack in the bottom of a large stock pot and fill with water. Bring to a boil over high heat, then carefully lower the jars into the pot using a holder. Water should be at least 1 inch above the tops of the jars, so add more boiling water if necessary. Bring the water back to a boil, cover the pot, and process for 10 minutes.
Remove the jars from the canner and place onto a cloth-covered or wood surface. Allow to cool overnight. Check that the jars have sealed by pressing on each lid with your finger. The lid should not move up or down at all.