It varies for every baby. Here's a general guide of a baby's teething timeline:
Four to seven months: teething begins
Five to seven months: first teeth emerge (usually on the bottom jaw, in the middle)
Six to eight months: upper middle teeth emerge
Nine to 12 months: upper and bottom teeth, next to the middle teeth emerge
12 to 15 months: first molars
16 to 22 months: canine teeth emerge
20 to 30 months: second molars (very back teeth) at the lower jaw emerge
25 to 33 months: second molars on the upper jaw emerge
Two to Three years: full set of baby teeth
In general, molars usually emerge between 12 to 15 months.