While more mothers have been participating in the paid workforce over recent years, the employment rate of lone mothers remains lower than that of couple mothers. This paper provides new insights into these different rates of employment, by examining whether the lower employment rate of lone mothers is due to their being less likely to enter employment, more likely to exit employment once employed, or a combination of both. Monthly calendar data from the Household, Income and Labour Dynamics in Australia (HILDA) survey are used to identify and compare the rate at which lone and couple mothers move into and out of employment over a seven-year period. These data show that of those employed in a one-month period, lone mothers are more likely to transition out of employment than couple mothers; however, not-employed lone and couple mothers are no different in their likelihood of transition into employment. These analyses also show that educational attainment, work history and age of youngest child may contribute to the different employment rates of lone and couple mothers.