David John Twardzik (born September 20, 1950) is an American former professional basketball player.

He is best known for being a key starting guard on the Portland Trail Blazers team that won the 1977 NBA Finals.

Twardzik grew up in Middletown, Pennsylvania, and played collegiately at Old Dominion University, where he was a two-time All-American and led the Monarchs to the 1971 NCAA Division II title game.

Twardzik played for the Squires for four seasons until the team (and the ABA) came to an end, folding just prior to the ABA-NBA merger in June 1976.

He has also worked for the Detroit Pistons, Charlotte Hornets, Los Angeles Clippers, Golden State Warriors, and the Denver Nuggets.