EXHIBIT 11

UNITIL CORPORATION AND SUBSIDIARY COMPANIES

COMPUTATION OF EARNINGS PER WEIGHTED AVERAGE COMMON SHARE OUTSTANDING

(Millions except common shares and per share data)

(UNAUDITED)



|                                                                       |  |                             |        |                           |      |   |       |  |      |        |  |   |      
|---------------------------------------------------------------------- |  | --------------------------- | ------ | ------------------------- | ---- | - | ----- |  | ---- | ------ |  | - | -----
|                                                                       |  | Three Months EndedJune 
30, |        | Six Months EndedJune 
30,
|                                                                       |  | 2010                        |        |                           | 2009 |   | 2010  |  | 2009
|Net Income (Loss)                                                      |  | $                           | (2.0   | )                         |      | $ | 0.3   |  | $    | 4.5    |  | $ | 9.4  
|Less: Dividend Requirements on Preferred Stock                         |  |                             | 0.1    |                           |      |   | 0.1   |  |      | 0.1    |  |   | 0.1  
|                                                                       |  |                             |        |                           |      |   |       |  |      |        |  |   |      
|                                                                       |  |                             |        |                          
|Net Income Applicable to Common Stock                                  |  | $                           | (2.1   | )                         |      | $ | 0.2   |  | $    | 4.4    |  | $ | 9.3  
|                                                                       |  |                             |        |                           |      |   |       |  |      |        |  |   |      
|                                                                       |  |                             |        |                          
|Weighted Average Number of Common Shares Outstanding  Basic (000s)   |  |                             | 10,820 |                           |      |   | 9,014 |  |      | 10,810 |  |   | 8,516
|                                                                       |  |                             |        |                          
|Dilutive Effect of Stock Options and Restricted Stock (000s)          |  |                             |       |                           |      |   |      |  |      | 1      |  |   |     
|                                                                       |  |                             |        |                          
|Weighted Average Number of Common Shares Outstanding  Diluted (000s) |  |                             | 10,820 |                           |      |   | 9,014 |  |      | 10,811 |  |   | 8,516
|                                                                       |  |                             |        |                          
|Earnings Per Share  Basic and Diluted                                 |  | $                           | (0.19  | )                         |      | $ | 0.03  |  | $    | 0.41   |  | $ | 1.10