While membership is open to all, members typically involve those with the same sept/surname that is shared by the Donnachaidh Clan.
The main surname used by Clan Donnachaidh is Robertson, which is also used by the present chief’s family, though other names are associated with the clan, the most common being Duncan and Reid. Other names associated with the clan may include:
| Collier | Donica | MacConnichie | MacRobbie | Robison |
| Colyear | Donnachie | MacDonachie | MacRobert | Robson |
| Conlow | Duncan | MacInroy | MacRobie | Roy |
| Connachie | Duncanson | MacIver | MacWilliam | Stark |
| Dobbie | Dunkeson | MacIvor | Reed | Tannoch |
| Dobieson | Dunnachie | MacLagan | Reid | Tannochy |
| Dobinson | Inches | MacLaggan | Robb | |
| Dobson | MacConachie | MacRob | Roberts | |
| Donachie | MacConlogue | MacRobb | Robertson |
To view more information on the septs and surnames click here