Silyl substituted polymers of polycycloolefins are provided as well as catalyst systems for their preparation. The polymers of the invention include polycyclic repeat units that contain pendant silyl functional groups represented by the following formulae: ##STR1## wherein A is a divalent radical selected from the following structures: ##STR2## R.sup.9 independently represents hydrogen, methyl, or ethyl; R.sup.10, R.sup.11, and R.sup.12 independently represent halogen, linear or branched (C.sub.1 to C.sub.20) alkyl, linear or branched (C.sub.1 to C.sub.20) alkoxy, linear or branched (C.sub.1 to C.sub.20) alkyl carbonyloxy, (C.sub.1 to C.sub.20) alkyl peroxy, and substituted or unsubstituted (C.sub.6 to C.sub.20) aryloxy; R.sup.10, R.sup.11, and R.sup.12 together with the silicon atom to which they are attached form the group: ##STR3## n is a number from 0 to 5; and n' is 0 or 1; and n" is a number from 0 to 10.