The penalties came after both failed pre-race inspections Saturday at Texas Motor Speedway prior to the NRA 500, resulting in race officials hauling away suspension mounting hardware.
Keselowski, the defending Sprint Cup series champion, was penalized 25 points, dropping him from second to fourth in the standings. No. 2 car crew chief Pat Wolfe was suspended for six races and fined $100,000.
Logano was penalized 25 points, knocking him from ninth to 14th, while his No. 22 car crew chief Todd Gordon received the same penalties as Wolfe.
Car owners Roger Penske and Walt Czarnecki were also docked 25 points.
A statement from NASCAR said both the No. 2 and No. 22 cars "were found to be in violation of Sections 12-1; 12-4J and 20-12 (all suspension systems and components must be approved by NASCAR)."
Penske Racing indicated it would appeal the penalties.
Second-place finisher Martin Truex Jr. received a six-point penalty because his car was found in an inspection after the race to be too low.