<P> The following year in the tenth season , 1969 - 1970 , Steve remarries , taking widowed teacher Barbara Harper ( Beverly Garland ) as his wife ; she brings with her a 5 - year - old daughter , Dorothy `` Dodie '' ( Dawn Lyn ) , so Steven now had a stepdaughter whom he also subsequently adopts . ( Dodie is wary of Steve at first , believing that he wants her to simply forget her late father , until he explains that he wants her to always remember and love him , but since he 's no longer alive , Steve wants to raise her in his place , and hopes she 'll come to love him also . ) Also , the last year - and - a-half of the series feature fewer appearances of both Don Grady and Stanley Livingston . Grady 's character was written out of the show at the end of the 11th season , which allowed for his wife Katie and their triplet sons to remain within the Douglas household the following season ( as a structural engineer Robbie was working on a bridge construction in Peru ) . Chip and his teenaged wife Polly ( Ronne Troup ) ( who eloped after Polly 's disciplinarian father refused to sanction their marriage ) move into their own apartment . </P>
<P> The following year in the tenth season , 1969 - 1970 , Steve remarries , taking widowed teacher Barbara Harper ( Beverly Garland ) as his wife ; she brings with her a 5 - year - old daughter , Dorothy `` Dodie '' ( Dawn Lyn ) , so Steven now had a stepdaughter whom he also subsequently adopts . ( Dodie is wary of Steve at first , believing that he wants her to simply forget her late father , until he explains that he wants her to always remember and love him , but since he 's no longer alive , Steve wants to raise her in his place , and hopes she 'll come to love him also . ) Also , the last year - and - a-half of the series feature fewer appearances of both Don Grady and Stanley Livingston . Grady 's character was written out of the show at the end of the 11th season , which allowed for his wife Katie and their triplet sons to remain within the Douglas household the following season ( as a structural engineer Robbie was working on a bridge construction in Peru ) . Chip and his teenaged wife Polly ( Ronne Troup ) ( who eloped after Polly 's disciplinarian father refused to sanction their marriage ) move into their own apartment . </P>
who played fred macmurray 's wife on my three sons
who played fred macmurray 's wife on my three sons
Beverly Garland
Beverly Garland