Tidal interactions between planets and their host stars are not well understood, but may be an important factor in their formation, structure and evolution. Previous studies suggest that these tidal interactions may be responsible for discrepancies between the ages of exoplanet host stars estimated using stellar models (isochronal ages) and age estimates based on the stars’ rotation periods (gyrochronological ages). We have compiled a sample of 28 transiting exoplanet host stars with measured rotation periods, including two stars (HAT- P-21 and WASP-5) for which we use data from the WASP survey to measure the rotation periods from the star-spot modulation of the light curve for the first time. The gyrochronological age is significantly less than the isochronal age for about half of the stars in our sample. Tidal interactions between the star and planet are a reasonable explanation for this discrepancy in some cases, but not all.