yes but it will take some investigation, a multimeter, some terminal blocks and some common sense? do you have any of these things?
you need to find which red is the switch wire from the 3 you have..
with a multimeter set to continuity
( and the power off ), at the light, connect the red to the earth wire.
now test between the earths in the switch and the reds until you get 0 on the meter ( or close to it ) and / or the meter beeps at you..
this red is the switch wire.. put a mark on it with a markerpen or something so you don't loose it..
put the light back how it was before you continue.
now..
the wire you just found is the switch wire this goes in whichever is the switch wire hole on the dimmer ( might be marked as L1, or maybe OUT etc.. consult your dimmer instructions to see which )
the remaining reds go together in the live of the dimmer ( might be marked as ~, IN, LIVE, COM etc, again consult your dimmer instructions. )
the blacks are all neutrals and go together in some terminal block in the back of the box..
earths together and to anything metal ( if it's a plastic box and plastic dimmer, stick them in a terminal block like the neutrals and tuck into the back of the box. )