Turgott has risen through the Academy ranks at Upton Park and is a regular for the club's Under-21 Development side, although he is yet to make his first-team debut for the Hammers.
The 19-year-old spent the majority of last season on loan at Bradford, making a total of 11 appearances.
Tozer, meanwhile, arrives to boost the U's options at the heart of defence and is a welcome addition having made 16 outings for the Cobblers this term, the most recent of which coming as a late substitute in the club's midweek draw at Chesterfield.
Tozer, 23, signed for Northampton from Newcastle in the summer of 2011 following two successful loan spells.
The pair will remain at the Weston Homes Community Stadium until January 4 and could make their debuts in Saturday's trip to Tranmere.